A century before Jack the Ripper haunted the streets of London, another predator held sway. In the late eighteenth century, the city was gripped by fear, outrage, and Monster Mania. A psychopath who had lashed out violently at over fifty women during a two-year crime spree roamed the city. After stalking and verbally harassing his unsuspecting victims, the Monster would assault them with blades shrewdly crafted for his methods of attack. Sometimes he jabbed his victims squarely in the hips and buttocks. Some he kicked in the backside with knives fastened to his knee. Others he invited to smell an artificial nosegay, only to stab the fine lady right in the nose with a sharp spike hidden within the flowers.

The details of these encounters—the bloodshed, the women's ripped clothing, the dark figure calmly observing his victim's screams of anguish before disappearing down the closest alley seconds before help arrived—became deeply ingrained in London's collective psyche. After an immense reward was offered for the capture of the perpetrator by the wealthy philanthropist John Julius Angerstein, one of the founders of Lloyd's, the public's excitement rose. Armed vigilantes patrolling the streets only added to the mayhem, and newspaper reports of each attack roused even greater panic. Fashionable ladies did not dare walk outdoors without copper pans over their petticoats to protect them against the Monster's rapier. And still, the attacks continued.

Finally in June 1790, an ungainly young Welshman named Rhynwick Williams, who worked in a factory for artificial flowers, was arrested as the London Monster. He appeared an unlikely Monster, with a reasonable alibi for one of the worst attacks. But after two long, ludicrous trials, where he was defended energetically by the eccentric Irish poet, Theophilus Swift, Williams was convicted.

Was Rhynwick Williams guilty after all? Or was he unlucky enough to fall into the hands of authorities when they needed someone, anyone, to pay for the Monster's peculiar crimes? Was there even a Monster at all? Considerable doubt has been cast. In The London Monster, Jan Bondeson writes a lively, detailed account of one of London's most notorious sons and assesses evidence for the guilt or innocence of the convicted Williams. He presents a wealth of contemporary evidence from learned and popular sources, as well as research on mass hysterias and moral panics, to reinterpret Monster Mania and compare it to historical and modern instances of similar phenomena. Indeed, in the magnitude of public frenzy it incited, the story of the London Monster bears similarities to the Ripper murders in 1888; in its stature as urban legend, it is of the bogeyman tradition of Sweeney Todd, the Demon Barber of Fleet Street. As Bondeson reveals, the London Monster occupies a unique space in London's criminal history and imagination, somewhere between fact and fiction.