As the novel is Older Than Radio and most of its twists are now widely known, all spoilers for the book are unmarked on this page. Spoilers for later adaptations may still be tagged and hidden.

Source of the Jekyll & Hyde trope, this 1886 novel by Robert Louis Stevenson begins with a mystery. When a girl is brutally assaulted late one night, her attacker, calling himself Mr. Edward Hyde, pays off the witnesses with a cheque signed by the eminently respectable scientist Dr. Henry Jekyll.

Jekyll's friend and attorney, Gabriel John Utterson, is disturbed when he learns this — because Jekyll has just recently made Hyde the heir to his £250,000 estate. Utterson starts to wonder if his client is being blackmailed, though Jekyll himself assures him that there is nothing to worry about.

While Utterson continues to investigate his suspicions, Hyde is seen committing the savage murder of Sir Danvers Carew, a prominent Member of Parliament. Jekyll is clearly upset at this development, though he again reassures Utterson that everything is fine and reveals that Hyde has left him a note apologizing for everything and promising he shall not return.

Two months pass, during which time Jekyll seems to be at peace again, until his butler Poole contacts Utterson to report that a stranger has locked himself inside the doctor's lab. When they break into the room they find Hyde, having committed suicide by poison — and two letters explaining everything...

The book can be read online for free here.

There have been several adaptations and parodies of this book. What makes them particularly interesting is not that each one changes, deletes, or adds certain elements; but that they tend to make the same changes. In addition to, or instead of, the above story, here's what you'll usually find in film and stage versions:

• Cutting the Twist Ending. The book is presented as a mystery, with the identity of Hyde as the surprise. But this is absent from most adaptations, mainly because invokedthe twist is now too famous to surprise anyone. As part of this, Mr. Utterson, the POV character for most of the book who drives the plot as he tries to find out what is going on with Jekyll, is almost always Demoted to Extra or Adapted Out. Similarly, Hyde reverts to Jekyll upon death rather than remaining Hyde.
• The physical appearance of Hyde. Films typically show Hyde as more physically-formidable than Jekyll (even huge and super-human in some versions), whereas in the novel Jekyll is well-built and Hyde, representing Jekyll's less-developed evil urges, is smaller than average. While Hyde is described as apelike and ugly, some adaptations have portrayed Hyde as more attractive than Jekyll.
• The nature of his split personality. In adaptations set in the modern-day, Jekyll is usually unaware or only vaguely-conscious of Hyde, suffering from split-personality amnesia. The book suggests that Jekyll remembers everything he does as Hyde, begins to find his own depravity horrifying and tries to dissociate himself from it. Hyde himself has unclear memories of what Jekyll does. The book makes it clear that Hyde isn't even a split personality, just chemically created secret identity that Jekyll comes to believe is a different personality during a mental breakdown fueled by guilt, stress and Never My Fault tendencies.
• The Love Interest. Jekyll's good girl fiancée and Hyde's promiscuous barmaid/prostitute girlfriend. This plot thread, not part of the original story, occurs in almost all adaptations. In the book, no women have major roles.

The novel provides examples of:

• Amateur Sleuth: Utterson is a lawyer by trade but spends the bulk of the novel investigating Dr. Jekyll and his association with Mr. Hyde.
• Ambiguous Time Period: Due to Year X being involved the most we know is that Jekyll was born in the 1800s and the story is set in the 1800s. The setting could just as easily be the 1850s if Jekyll was born in 1800, or the 1890s. The extent of our knowledge is that it is the Victorian era.
• And Some Other Stuff: Lanyon recognizes a few of the ingredients used to make the potion (salt, phosphorous, blood-red liquor, ether), but the rest are unidentified; he speculates that they're of Jekyll's private manufacture, however.
• Apocalyptic Log: The Reveal comes in two of these, one left by Dr. Lanyon, giving an account of how Jekyll revealed his secret to him, and the second a confession by Jekyll himself, written after he could no longer make the formula and realized Hyde would take over completely. Both are read by Utterson and they make up Chapters 9 and 10.
• Applied Phlebotinum: A drug is the means by which Hyde is created. This was a time when chemistry, and especially the workings of the human mind, were still relatively unknown, and therefore could be used in the same way radiation was used as a reason for giant monsters and superpowers in the 1950s.
• Bastard Bastard: Hyde is not only smaller but younger-looking than Jekyll, and Utterson briefly wonders if he's the by-blow of Jekyll's youthful indiscretions.
  "Poor Harry Jekyll," he thought, "my mind misgives me; he is in deep waters! He was wild when he was young; a long while ago to be sure; but in the law of God, there is no statute of limitations. Ay, it must be that; the ghost of some old sin, the cancer of some concealed disgrace: punishment coming, pede claudo, years after memory has forgotten and self-love condoned the fault."
• Better to Die than Be Killed: Either Hyde or Jekyll decides to take cyanide rather than be caught and hanged by the police.
• Big Bad: Edward Hyde, Jekyll's evil given form.
• Bitter Almonds: Hyde takes cyanide to kill himself, which Utterson identifies by "the strong smell of [almond] kernels that hung in the air".
• Blackmail: Near the beginning of the book, Jekyll has changed his will to leave everything to Hyde. The protagonists believe Hyde is blackmailing Jekyll and vow to find out how.
• Body Horror: Though not pushed as far as later writers went with it, the transformation from Jekyll to Hyde and back is quite graphically detailed, with his features melting and altering while his bones grind and reform.
• Cane Fu: Hyde beats Sir Danvers Carew to death with Jekyll's cane.
• The Case of...: One of the earliest works to use this intriguing title template.
• Chromosome Casting: The only female characters are several of Hyde's victims mentioned in passing, a maid who witnesses Hyde's first murder, Hyde's landlady and Jekyll's cook. None are given names.
• A Darker Me: This is the appeal of Hyde for Jekyll; he even refers to Hyde as "the darker side of my nature".
  Jekyll: This, too, was myself. It seemed natural and human.
• Dead Man Writing:
  • Lanyon wrote a complete briefing about the night where Edward Hyde came to his house, took the potion, and turned into Jekyll. This is when The Reveal happens. Lanyon leaves instructions that the letter mustn't be opened before the disappearance or death of Henry Jekyll.
  • That's directly followed by the last chapter of the book, the letter that Henry Jekyll writes after he takes the last sample of his potion, in which he explains the case.
• Death of Personality: Jekyll's letter explains that no matter what happens to him as Hyde, Jekyll will be dead.
• Didn't Think This Through: Hyde is a creature of pure instinct and impulse, seeking only immediate gratification of his urges without the caution or restraint that Jekyll possesses. This becomes most apparent with the murder of Sir Danvers Carew, which Jekyll in his final statement acknowledges was a result of Hyde's fury at being locked up when Jekyll for a period went without consuming his potion — while he wants to do something so foul that it would stain the good doctor's conscience forever, in murdering Carew he guarantees that Hyde will become the most wanted man in the country, with no friends or allies to turn to, and so must remain concealed within Jekyll or else face the gallows.
• Dirty Coward: Hyde's sense of self-preservation makes him fearful of anything that could harm him. He and Jekyll spend their last days locked in the cabinet, moping and weeping over fear of being caught by the police.
• Does This Remind You of Anything?:
  • The book is a thinly veiled metaphor for drug or alcohol addiction. In the beginning, Jekyll enjoys being Hyde, because it gives him a feeling of freedom and the means to cut loose in ways he is normally too restrained by both normal social manners and his moral compass to allow himself to do, so he more and more frequently indulges in being Hyde. When Utterson mentions his concern over the situation, Jekyll says that it isn't bad and he could get rid of Hyde at any moment if he wanted. But Jekyll gradually loses control over Hyde, who starts to take over his life and even eventually become the dominant persona, and the elixir goes from becoming a way for Jekyll to indulge himself to the only way he can stay "normal" for a while. Stevenson was an opium user.
  • The description of Sir Danvers' beauty, thought by some to make him sound rather camp, also gets read like this.
• Downer Ending: Jekyll is transformed permanently into Hyde, and then dies by his own hand. Utterson, having failed to save his friend, is left to pick up the pieces.
• Driven to Suicide: After Jekyll realizes that Hyde will take all control of him — both of his body and his personality — he restrains himself to his lab until the final transformation. Hyde takes cyanide when Utterson shows up outside the lab and demands to see Jekyll.
• Epileptic Trees: In-universe, Jekyll speculates that man is more than two and he only says two because others will go farther than he did, and that if he'd taken the potion with nobler intentions it may have made him purely good instead of purely evil. Whether he's right or wrong about any of this is never revealed.
• Evil Feels Good: This is the reason Jekyll thinks separating his evil side from his good side is a good idea. As Hyde, he's free to do anything without restraint from the law or his own conscience; with Jekyll being guiltless because Hyde is the one committing the crimes.
• Evil Is Bigger: Inverted. Jekyll becomes a dwarf when he transforms into Hyde, which is speculated to be a physical manifestation of all his good impulses disappearing.
• Evil Is Not a Toy: Releasing Hyde was easy. Getting rid of him proved impossible except via death.
• Evil Makes You Ugly: Played with. Hyde "gave an impression of deformity without any nameable malformation" — that is, he isn't ugly in physical appearance, but something about him instinctively repels people. His attitude and behaviour are described with adjectives such as "troglodytic" and "ape-like" which also contributes to the impression of ugliness. Jekyll theorized that there is an instinctive disgust and hatred when people faces pure evil.
• Extra! Extra! Read All About It!: "Special edition! Shocking murder of MP!" serves as the funeral oration of Sir Danvers Carew, following his murder by Hyde.
• Fantastic Drug: Jekyll makes a potion that brings out his evil side, which quickly spirals out of control. Some adaptations further the drug metaphor and have him inject the formula rather than drink it. Edge of Sanity, a 1989 adaptation starring Anthony Perkins, goes so far as to have him smoke it out of what is apparently a Victorian-era crack pipe!
• Foreshadowing:
  • The first hint we have of Jekyll and Hyde being the same is the handwriting of a letter. The idea is that Utterson has been told by Jekyll that the letter, supposedly written by Hyde, was handed in soon after the murder of the politican, but Jekyll's butler says nothing has been delivered in such a manner recently. Utterson's clerk then notices that the handwriting of Jekyll is similar to the handwriting in the letter. Utterson's first thoughts are that Jekyll faked the letter to cover for Hyde.
    Utterson: (thoughts) What! Henry Jekyll forge for a murderer?
  • In chapter 1, the door of a house is described as sinister: it "was blistered and distained, and bore in every feature, the marks of prolonged and sordid negligence." That's the door where Enfield told Utterson he saw Mr. Hyde enter. In Chapter 2, Utterson goes to the house of Dr. Jekyll, whose door is described as "with the air of great wealth and comfort," and he asks the butler, Poole, if Mr. Hyde has the key to the old dissection room. In chapter 7, Enfield realizes the first door is the back door of Dr. Jekyll's house: Both doors, the sinister one and the comfortable one, belonged to the same house. Also, Dr. Jekyll's hall is described as "a pet fancy of… the doctor's; and Utterson himself was wont to speak of it as the pleasantest room in London." In contrast, the old dissection room is described as: "the tables laden with chemical apparatus, the floor strewn with crates and littered with packing straw, and the light falling dimly through the foggy cupola."
• Go Mad from the Revelation: Dr. Lanyon after he sees Hyde transform into Jekyll for the first time. It ends up killing him.
  Lanyon: I have had a shock, and I shall never recover. It is a question of weeks.
• Gone Horribly Wrong: The potion was supposed to completely separate the good and evil sides. Instead, it just separated the evil side, meaning that Jekyll was never pure good to balance out the pure evil. Jekyll considers this a good thing at first, because it allows him to act out all his repressed evil urges. Doing that works out pretty well, until the Split-Personality Takeover starts kicking in.
• Good Is Boring: Jekyll thinks so, which is what drove him to create the potion that let him turn into Mr. Hyde in the first place, and why he indulged as often and as often as he did. As far as he's concerned, the virtuous life of Dr. Jekyll is too dull to endure.
• Good Is Impotent: After turning into Hyde in broad daylight, Jekyll notes that while he would have been too stunned to act, Hyde was proactive and set on his immediate goals.
• Hair-Trigger Temper: A minor annoyance in conversation with Sir Danvers Carew causes Hyde to fly into a rage and beat him to death.
• Have a Gay Old Time:
  • Here is how Mr. Enfield explains his reluctance to start asking questions about other people's business ^note "Queer Street" referred to Carey Street, where London's bankruptcy courts were located - saying it essentially implies someone is in difficulty, typically financial:
    "...the more it looks like Queer Street, the less I ask."
  • Then there's how Jekyll describes the duality of man, using an old word for a bundle of sticks:
    "It was the curse of mankind that these incongruous faggots were thus bound together..."
• Hearing Voices: After a certain point Jekyll was able to hear Hyde inside his head, constantly demanding to get out.
• Hidden Depths: A key theme of the novel. Even leaving aside the obvious example of the pious and high-minded Dr Jekyll and his unsavoury shadow-persona Edward Hyde, almost every character is discussed and presented in terms that suggest hidden levels.
• Higher Self: The Fantastic Drug Dr. Jekyll drinks allows him to "disappear" his higher self, leaving only the lower self, Mr. Hyde.
• Hope Spot: After Hyde murders Sir Danvers, he disappears without a trace; Jekyll assures Utterson that he's cut off all contact with Hyde, and becomes much happier and more sociable with Hyde gone. Then Jekyll suddenly begins locking himself in his room and refusing to show himself to anyone, and things go downhill fast from there.
• Humanoid Abomination: Hyde is a fairly normal looking man, yet everyone who meets him feels that there is something physically wrong with him, as if he is ugly or deformed in some way that they just can't identify. The reveal that he is Jekyll's inner darkness incarnate implies that what they were picking up on was that Hyde is Made of Evil and that this was emanating from him in some way.
• Hypocrite: Jekyll does not take responsibility for the evil actions of Hyde, yet he takes the potion specifically to enjoy performing evil actions as Hyde. Stevenson called this Jekyll's Fatal Flaw in a letter to a friend. He also speculates at one point that, for all his high-minded rhetoric on the subject of curing people of their darker impulses, Hyde only exists in the first place because he drunk the potion with the hypocritical and self-serving desire to be able to indulge in all his darker desires guilt-free rather than for genuinely noble reasons.
• In-Series Nickname: While most people call Jekyll by his last name, or by "Henry," Utterson is close enough to call him "Harry."
• Involuntary Shapeshifter: After months of taking the potion, Jekyll suddenly found he had transformed into Hyde in his sleep upon waking up. After that scare, he swore off the potion for some time without incident, but then gave in to the urge. That was the night Hyde murdered Carew. Again, Jekyll stops taking the potion and now with firmer resolve, but after some time without it he suddenly spontaneously transforms in broad daylight, and from there it goes From Bad to Worse where he now needs the potion (which he's rapidly running out of) in greater doses more frequently just to revert back to Jekyll as he keeps spontaneously turning into Hyde.
• Irony: Jekyll creates Hyde so as to have a persona that can freely move in the world indulging in all the vices that Jekyll, constrained by his public persona, wants to but cannot without destroying his life and reputation. After murdering Carew, Jekyll is the persona that can freely move about while Hyde must, well, hide.
• It's All About Me: Jekyll invented the potion that would turn him into Hyde so he could indulge in his evil and "undignified" vices without guilt or fear of being caught. When he trampled the little girl and then later murdered Carrew, in both cases he was more upset that he got caught than that he hurt/killed someone, and measured them based solely on whether the crimes could be traced back to Jekyll's good name and reputation. In his final letter, Jekyll says that this was his greatest failing; he wanted to create an evil side free of guilt and a good side that would never have anything to feel guilty about, but since both those desires were selfish, he naturally could only achieve the former.
• Jekyll & Hyde: As the Trope Maker, the book naturally shows the unbuilt stage of this trope. Henry Jekyll, who is explicitly stated to be capable of both good and evil, deliberately created Edward Hyde for a selfish purpose and actually enjoyed what his darker side brought out until a murder was committed. He began to need more of the potion to ward off Hyde taking control, and when recreating the formula proved impossible he wrote a letter to explain everything before dying. In modern times, this is now an idiom that describes someone who is nice one minute, nasty the next, or someone who's outwardly respectable but leads a seedy double life.
• Left Hanging: We aren't shown how Utterson reacts to what he reads or what happens afterward.
• Let Us Never Speak of This Again: Utterson and Enfield vow to never speak of the incident at the crossroads to anyone. Jekyll also deflects suspicion from himself by asking his friends to not bring matters up.
• Loss of Inhibitions: This is the reason Dr. Jekyll created the potion that would turn him into Mr. Hyde. Jekyll wanted to indulge in his vices without having to fear the consequences, so the potion turned him into a person without restraint and allowed him to avoid suspicion from the law. Jekyll realizes the consequences of his decision too late when Hyde murders Danvers Carew.
• Miraculous Malfunction: An "impurity of salt" is what makes the transformation from Dr. Jekyll into Mr. Hyde possible. This is what finally dooms Jekyll — he only realizes it exists when his original salt batch runs low and the new ones he orders fail to induce the same effect because they are pure. In a time before modern methods like mass spectrometry, figuring out the accidental ingredient is impossible.
• Morally Ambiguous Doctorate: Jekyll, particularly in the original book, where his reason for continuing to imbibe the potion was to do bad things and not get caught. His alter-ego, Mr. Hyde, averts this.
• My God, What Have I Done?: Jekyll, after Hyde kills Carew, which is the point he can no longer bring himself to think Evil Feels Good. After this, he stops characterizing Hyde as being a part of himself, instead attempting to distance himself from the persona by referring to Hyde as a separate entity attempting to seize control of his body.
• The Napoleon: Hyde is frequently described as being "short," "small" and even "dwarfish," in contrast to the taller Jekyll. This is explained as being because Jekyll never indulged in his evilness before, so his evil side is "underdeveloped."
• Never My Fault: Even when writing his final letter, Jekyll still insists that, even now, he doesn't consider Hyde's actions his actions. His choice of pronouns says otherwise.
• No Plans, No Prototype, No Backup: This is an accident on Jekyll's part, as it turns out to be an unknown impurity that makes the stuff work.
• Noodle Incident:
  • Stevenson never goes into great detail about most of the things that Hyde does on his nightly escapades before crossing the invokedMoral Event Horizon by murdering Sir Danvers Carew for no reason; the narrative only states that his activities were of an evil and lustful nature. Given the Victorian England setting and what was considered abhorrent for the time, he may have been engaging with prostitutes and drinking heavily in shady taverns, possibly smoking opium, but we can only surmise. Jekyll's own youthful vices are likewise undescribed.
  • The maid that recognizes Hyde after Carew's murder mentions him visiting her master at least twice; the reasons for these visits go unspoken and the book never mentions it again.
  • What Lanyon and Jekyll talked about post-transformation isn't committed to paper, though they talked for at least an hour. Understandable as Lanyon is horrified by what just unfolded before him and eventually goes mad from the revelation, dying shortly afterwards.
• Obviously Evil: Hyde's appearance is banal, yet everyone who looks at him instinctively recognizes that he's evil.
• Once More, with Clarity: Dr. Jekyll's narrative at the end of the story gives the other perspective of the events that Utterson was investigating. Why did Jekyll shut himself up in the house? Because he started spontaneously changing into Hyde. Why did Jekyll have Utterson accept a will leaving all Jekyll's money to Hyde? Because Jekyll is Hyde. Why did Jekyll suddenly slam shut his window when he was having a pleasant chat with Utterson out in the street? Because he felt himself about to turn into Hyde at that very moment. Why did Henry Jekyll write a frantic letter to Lanyon to retrieve his chemicals, followed by Edward Hyde arriving and transforming into Jekyll before Lanyon's eyes? Because Jekyll transformed into Hyde without use of the drug, in broad daylight in a public park, and could not access his chemicals, so he had to send Lanyon to retrieve them.
• Professor Guinea Pig: The Ur-Example, beating out The Invisible Man by a decade. Jekyll tested his experimental formula on himself, and his logbook implies he's been doing it for years.
• Pint-Sized Powerhouse: Hyde is described as a small, impish man yet he possesses shocking strength. He tramples a girl in the street as though she wasn't even there and later beats Carew to death with so much force that the heavy wooden cane he's using snaps in half.
• Psycho Serum: The Trope Maker. Dr. Jekyll's potion separates and liberates his darker side, turning a regular man with good and bad aspects into an all-bad violent sociopath.
• Pure Is Not Good: Henry Jekyll, a man with mostly good and some evil urges, thinks that if he could separate his good and bad urges into separate identities, life would be better, because he would be free of morality and could indulge himself on every pleasurable vice without hypocrisy. Hyde himself is pure, but pure evil and cares for nothing but himself, only using Jekyll's form as a hiding place.
  • Also demonstrated by how Jekyll thinks that the reason the new salt he ordered for the potion didn't work was because the salt wasn't pure like the original salt he used, only to realize later on that it's more likely the original salt was impure and the potion worked precisely because of that unknown impurity.
• The Reveal: The reason Dr. Jekyll was helping Mr. Hyde is that they are the same person — Jekyll transformed into Hyde by means of a potion he created to separate a man's good and evil sides.
• Sex Is Evil, and I Am Horny: It is implied that among Jekyll's vices was womanizing. In his confession, the doctor characterizes "a certain impatient gaiety of disposition" as the worst of his vices. At the time, "gay" was used to describe a heterosexual person who was inordinately lustful.
• Shadow Archetype: Hyde is Jekyll's repressed depravity given form and a name.
• Slave to PR: Dr. Jekyll is very concerned with his good reputation and standing with the community. Part of what drove him to create the potion in the first place was to indulge his lower desires without caring, and he became Mr. Hyde as often and as long as he did so he could indulge his "undignified" urges without it being traced back to Dr. Jekyll's good name and standing. In fact, after trampling the girl and murdering Carew, in both cases, Jekyll cares only that both instances almost ruined his anonymity and could be traced back to Jekyll.
• Small Role, Big Impact:
  • Richard Enfield makes only two appearances in the whole novella, but him recounting his tale of Hyde to Utterson is what kicks off the rest of the story.
  • A maid recognizes Hyde after he murders Carew, making him a wanted fugitive unable to go about openly. Similarly, Carew only appears for a few paragraphs, but his murder is what drives Jekyll to have his Heel Realization and start trying to completely suppress Hyde.
• Split Personality: An unusual example in that Hyde is actually a secret identity, but due to Jekyll's Never My Fault tendencies and a Villainous Breakdown, he comes to believe it is the case.
• Split-Personality Takeover: Likely the Ur-Example. The more Jekyll takes the potion, the stronger Hyde's influence becomes, and it gets to the point where if he dozes off or even blinks he changes to Hyde. However, there is a twist: Hyde is not a split personality, but a secret identity, whom Jekyll comes to believe is a split personality due to a combination of his Never My Fault tendencies, a Villainous Breakdown and the fact that the transformation will soon be permanent.
• Spontaneous Crowd Formation: Despite Hyde running into the little girl at around 4 in the morning, a sizable crowd gathers around them. Downplayed somewhat, in that the crowd is mostly comprised of the girl's family as opposed to random passers-by (like Enfield and the Doctor).
• Technicolor Science: The potion starts out red and then turns purple before settling on green. When it doesn't change to green near the end, the potion does not work, and Jekyll realizes that he is truly screwed.
• The "The" Title Confusion: The book was first published as Strange Case of Dr Jekyll and Mr Hyde. Later reprintings added a "The" to the beginning.
• This Is Your Brain on Evil: The addiction metaphors are obvious and appropriately creepy. This was written at a time when the effects of opium addiction were just coming to light.
• Tuckerization: Stevenson named Jekyll after his friend Walter Jekyll, whose sister Gertrude became one of the most famous gardeners of her generation.
• Twist Ending: The twist of Jekyll and Hyde being the same person comes at about the 3/4 mark, and then closes out with Jekyll's own posthumous explanation for everything that happened.
• Unbuilt Trope: While it's easily the most well-known example of the split personality trope in pop culture and is now the shorthand for all such stories, it deviates from its successors in many ways. Most notably, rather than being an involuntary manifestation that he struggles to control and who shuts the original personality out, Jekyll's transformation into Hyde was entirely voluntary and he remains completely conscious and aware of what he does as Hyde and enjoys it immensely, at least at first, and it's made abundantly clear he is in serious denial as to his evil nature. The revelation that they are the same person is also treated as a genuine plot twist while most adaptations and most stories make that clear from the outset.
• Uncanny Valley: In-universe, this is how the other characters describe Hyde and recognize that he's not quite right. They always describe him as looking "deformed" somehow, despite having no outwardly noticeable disfigurements, and express a violent loathing of him at first sight despite being unable to find a particular point of disagreement.
• Unstoppable Rage: After Hyde goes into a rage and attacks Carew, he exults in the thrill of the evil action and beats the man to death.
• Wham Line: The following:
  Lanyon: (...) for there before my eyes—pale and shaken, and half fainting, and groping before him with his hands, like a man restored from death—there stood Henry Jekyll!
• Would Hurt a Child: In his first appearance Hyde literally walks over a little girl he meets on the street.
• Year X: Used several times. For instance, the Carew murder happened in October of 18— and in his statement, Jekyll writes that he was born in the year 18—.

Tropes common to multiple adaptations:

• Abled in the Adaptation: In the original story, Hyde is described several times as a dwarf. No screen adaptation has depicted him with dwarfism, some going as far as making him a giant.
• Adaptational Badass:
  • The part about Hyde being a diminutive man, much smaller than Jekyll, is usually adapted out. Instead, Hyde is usually portrayed as a burly brute of a man, larger than Jekyll, or the same size. (This is acknowledged in volume 2 of The League of Extraordinary Gentlemen, in which Hyde is basically the Hulk. Apparently he started out as the book version, but the more Jekyll indulges Hyde, the more powerful Hyde becomes.)
  • Some film adaptations give Lanyon a larger role, having him be the one to stop Hyde.
• Adaptation Expansion: This is inevitable, since the novella is quite short with a relatively slow beginning; it isn't until the murder of Carew at the half-way point that the plot begins to pick up speed.
• Adaptational Heroism: In the book Jekyll took the potion to indulge in his vices and evade responsibility and consequences for his actions, giving him freedom to do whatever he pleased. Most adaptations, however, have Jekyll as a humanitarian scientist who wanted to separate good from evil to eliminate wrong from the world, or a fundamentally good man who just wouldn't take no for an answer—albeit he still enjoys the freedom Hyde's form provides at first.
• Alternate Identity Amnesia: Adaptations set in the present day tend to have Jekyll not know what he does as Hyde, while the book, plays, musical, and earlier film versions have him remember everything he does.
• Artifact Title: A good number of adaptations preserve the "Strange Case" portion of the original title. To the modern audience, it's not much of a mystery anymore since adaptations typically show the story from Jekyll's point of view.
• Betty and Veronica: Many adaptations add contrasting female companionship options that weren't in the book, an innocent girlfriend/fiancée for Jekyll and for Hyde an earthier, more sexually available woman that he brutalizes.
• Demoted to Extra: The fate of Mr. Utterson, due to most adaptations centering on Jekyll from the start rather that Utterson investigating a mystery, as the novel did. In the 1920 film he pops up towards the end as one of Jekyll's friends, in the 1931 film he is an extra, and in the 1941 film he's completely omitted.
• Pragmatic Adaptation: Jekyll wasn't the central character of the original story—the story is told from the POV of Mr. Utterson, Jekyll's old friend and lawyer who investigates the mystery. Most of the story depicts Hyde's actions as being told about instead of shown. The twist ending was revealed in letters where everything is told instead of shown. Most adaptations, instead, focus on depicting Jekyll's dramatic struggle between his two selves and his eventual downfall, since everybody already knew the ending.
• Superpowered Evil Side: In many modern adaptations, such as Van Helsing and ITV's Jekyll and Hyde, Hyde possesses superhuman powers, most commonly inhuman strength.

The 1941 movie provides examples of:

• Adaptation Name Change:
  • Jekyll's fiancee went from Muriel Carew to Beatrix Emery, and Sir Danvers' name was also changed to Sir Charles Emery.
  • Because Ingrid Bergman was cast in the role, Ivy Pierson's last name is changed to the more Scandinavian-sounding Peterson.
• Animal Testing: Jekyll first tests his formulas on animals. Despite claiming none of them died, when he returns from an outing he discovers they're all dead.
• Bloodless Carnage: Hyde gets shot three times by Lanyon, no bullet holes are visible anywhere on him.
• Book Ends: The film begins and ends with Psalm 23 ("The Lord is My Shepherd..."); Sung as a Church hymn in the opening, and then spoken as a prayer by Poole at the closing.
• Boyfriend-Blocking Dad: Beatrix' father Sir Charles is a subversion; he's wary of Jekyll at first, but eventually comes to support his daughter's romance with him and insist the two wed as soon as possible.
• Chew-Out Fake-Out: Sir Charles confronts Jekyll and Beatrix and says he won't stand for their tawdry affair any longer. Jekyll and Beatrix are worried that he's going to force them apart… only for the old man to instead enthusiastically insist the two get married at once.
• Composite Character: Lanyon takes Utterson's role as Jekyll's friend who helps investigate Hyde and Lanyon's role as a skeptical doctor who first sees him transform.
• Evil Is Petty: Some of Hyde's misdeeds include tripping a waiter with his cane and refusing to pay a chauffeur who just gave him a ride.
• Gory Discretion Shot:
  • What Hyde did to Ivy's back is only seen by the other characters.
  • Later, it's made clear that he strangles Ivy and beats Beatrix's father to death, but in both cases the victim is kept just off-screen.
• Have a Gay Old Time: "Gay" is used to mean "happy" once or twice throughout.
• Hope Spot:
  • After Beatrix's return to London, the planning of their wedding date, and learning how Hyde had abused Ivy, Jekyll swears to avoid the Hyde personality altogether. Things don't work out.
  • Jekyll breaks up with Beatrix, leaving her crying. He turns back (in a Knee-High Perspective) to which Beatrix responds as an act of reconciliation...until she sees it is Mr. Hyde who has returned.
• How They Treat the Help: Subverted; Mr. Hyde gives a waiter at the bar a very generous tip, saying the man has a family to provide for and claiming to empathize with him… then when the waiter turns to leave, Hyde uses his cane to trip the waiter down a flight of stairs just to be a dick.
• Lighter and Softer: Due to the implementation of the Hays Code, the violence and sexual content is toned down from the '31 movie.
• Line-of-Sight Name: After receiving a letter from Lanyon worrying about Jekyll, Bea improvises a letter from Jekyll by looking at a newspaper next to it.
• Mirror Scare: In a moment reused from the 1931 film. Ivy, having just (so she thinks) escaped Hyde's grasp, sits in front of her mirror and toasts herself. Just as she finishes raising the glass, the door opens.
• Not Even Bothering with the Accent:
  • Tracy, like March before him, doesn't even try for any kind of British accent.
  • Bergman, while speaking dialogue that is Cockney in vocabulary and phrasing, keeps her Swedish accent.
• Rape Discretion Shot: When Hyde gives Ivy a lift home after getting her fired, the shot fades to black as he looms over her and she says, "No... no..."
• The Remake: The movie is a direct remake of the 1931 version and was made to eclipse it in popularity, to the point that the studio bought the rights to the previous film and tried to have all existing prints destroyed.
• Shell-Shocked Veteran: Jekyll is inspired in his experiments by a man who lost his mind after an explosion. Jekyll believes that he's not insane, but merely letting his evil side completely consume him.
• Visual Innuendo: During one of the hallucinatory montages when Jekyll transforms into Hyde, he has a vision of Ivy the barmaid's head as the cork in a champagne bottle—and the cork pops.

Will Hyde die upon the scaffold? or will he find courage to release himself at the last moment? God knows; I am careless; this is my true hour of death, and what is to follow concerns another than myself. Here then, as I lay down the pen and proceed to seal up my confession, I bring the life of that unhappy Henry Jekyll to an end.