Violent crime has long been associated with ideas of insane and/or intrinsically dangerous masculinities in the global north. Victorian Gothic literature, generated during a period when positivist discourse around dangerousness, madness and crime was gaining in authority and coherence, provides particularly useful insights into the narratives underpinning these associations. This paper focuses on the Strange Case of Dr Jekyll and Mr Hyde (1886), which, being a work of cautionary horror written during an era of powerful cultural fascination with violent urban crime is particularly rich in such discourse. A range of methodological tools borrowed from literary criticism, legal studies and discourse analysis turn Stevenson's novella into a penetrative lens to examine the anxieties of 19th century medico-legal thinking. The many layers of the Jekyll-Hyde binary are analysed along a series of other relevant binaries that characterise many Victorian narratives around crime: reason against insanity, normativity against deviance, and respectable bourgeois masculinities against uncontrollable working-class masculinities, whose savage sexuality poses a threat to social order. Contextualised historically as part of the wider fin de siècle preoccupation with degeneration theory, as well as legally, having followed a long series of legislative and policing moves to control the disconcerting underclasses amassing in urban spaces, the Strange Case of Dr Jekyll and Mr Hyde arises as a uniquely informative testament of the profound contradictions of a terrified post-Industrial Revolution Europe – what Moretti (1982) would call a dialectic of fear. Narratives such as the ones unfurling in the Strange Case are not, however, taken as mere reflections of the activities and anxieties of the Victorian medico-legal apparatus. Rather, this paper finds that the tensions permeating the novella constitute elements of a wider narrative construct whose main achievement was the validation and naturalisation of a deeply rigid social taxonomy, justifying the exertion of social and legal control upon populations inscribed as monstrous and Other. Keywords: Law and Literature, Criminology, Victorian Studies, Masculinities, Legal Psychiatry