Robert Louis Stevenson’s The Strange Case of Dr. Jekyll and Mr. Hyde is an important gothic-science fiction novel that follows the basic template established by Mary Wollstonecraft Shelley in Frankenstein: Or, The Modern Prometheus in 1818. In both novels a well-educated man conducts secret experiments that soon run out of control. The result of these experiments is the release of an uncanny double, or doppelganger, who wreaks destruction upon the immediate domestic and social circle of its creator. Both works provoke discussion about the appropriate limits of human ambition, and they question whether or not humans—as flawed individuals—should be granted unlimited scientific knowledge.

The Strange Case of Dr. Jekyll and Mr. Hyde is also linked to the gothic detective fiction form. In this mode of the detective story, multiple narrators provide competing eyewitness accounts of uncanny and disturbing events, and the rational detective figure (Mr. Utterson) must attempt to make sense of events.

The central feature of The Strange Case of Dr. Jekyll and Mr. Hyde is its theme of duality. Two personalities—opposite and antagonistic—mesh within one body, and as such the novel has a rich potential for psychoanalytic criticism. In many ways, Jekyll can be seen as the superego, that portion of the human consciousness that attempts to control the physical urges of the id (here represented by Edward Hyde) and filter them through socially appropriate activities. However, when the id is repressed rather than integrated into a functioning psyche, the individual’s behavior will grow increasingly erratic. It is inevitable that, in time, whatever is repressed will once again become manifest. What then occurs is what psychologists call the return of the repressed.

In Stevenson’s work, Dr. Jekyll is increasingly unable to control his alter ego; his identity becomes fragmented into Jekyll and Hyde, and then the Hyde persona begins to manifest itself unexpectedly. The id, as manifested in the persona of Hyde, requires ever more extreme forms of repression (such as a complete suppression of this identity through Jekyll’s refusal to take the drug that causes the transformation). The most extreme form of repression is self-annihilation, as readers see when Jekyll kills himself to repress Hyde.

A question frequently asked about the novel is the nature of what is being repressed by Jekyll. What, precisely, are the strange vices that Jekyll feels so compelled to act upon? The two most provocative answers are homosexual desire and drug abuse. Stevenson’s The Strange Case of Dr. Jekyll and Mr. Hyde is linked to other late nineteenth century, Decadent-era works, such as Oscar Wilde’s The Picture of Dorian Gray (1890, serial; 1891; expanded) and Bram Stoker’s Dracula (1897). These novels explore the seamy side of London life (for example, drug use) and, in particular, explore homoerotic and homosexual themes. Jekyll, Hyde, Utterson, Enfield, Lanyon, and Sir Danvers Carew are each middle-age bachelors who, within the course of the book, never interact with women. They walk the streets of London at night and meet up with each other. They have secret lives and write secret letters with enclosed, sealed missives. From an early age, Jekyll had desires that were not socially acceptable. He was driven to create a secret identity so as to be able to act upon these irresistible urges. In the end, the cost of living a double life is too much for him, and he commits suicide.

As a novel exploring the effects of drug use, The Strange Case of Dr. Jekyll and Mr. Hyde reveals Jekyll’s increasingly desperate need for drugs, his inability to control his body without the use of drugs, and the mood swings and physical abnormalities caused by repeated drug use, drug withdrawal, and the ever-increasing dosage needed to obtain highs.

Other critics link The Strange Case of Dr. Jekyll and Mr. Hyde to a particular concern of the post-Darwinian world of the late nineteenth century: the fear that British society had become too civilized, too cultured. British men, it was feared, had become effete and no longer able to lead the British Empire. This fear that British men were not “manly” enough had the potential to destabilize England’s sense of leadership and cultural superiority. After all, the British defended their subjugation of other nations (particularly the “darker” peoples of Africa, India, and Asia) by insisting that the British were more highly evolved and more moral than other races and ethnicities. Hyde, who is darker, stronger, and more primitive than the effeminate Jekyll, might represent either a devolution of the human species or an interpolation of the primitive other within the confined and controlled world of British men. In either case, the logic of what is today called social Darwinism can be shown to underpin the racial and gender anxieties of The Strange Case of Dr. Jekyll and Mr. Hyde. Hyde is an other whose very presence threatens the safe and secure world of these men.