On 8 December 1854, Emmanuel Barthelemy visited 73 Warren Street in the heart of radical London for the very last time. Within half an hour, two men were dead. The newspapers of Victorian England were soon in a frenzy. Who was this foreigner come to British shores to slay two upstanding subjects? But Barthelemy was no ordinary criminal... Marc Mulholland reveals the true story of one of nineteenth-century London's most notorious murderers and revolutionaries. Following in Barthelemy's footsteps, he leads us from the barricades of the French capital to the English fireside of Karl Marx, and the dangling noose of London's Newgate prison, shining a light into a dark underworld of conspiracy, rebellion and fatal idealism. The Murderer of Warren Street is a thrilling portrait of a troubled man in troubled times - full of resonance for our own terrorised age.