The Shadow of Frankenstein (The Empire of the Necromancers 1)

1821. Thanks to the technique recently discovered by Victor Frankenstein, it is now possible to resurrect the dead. The British Crown put their best man, former Scotland Yard Superintendent Gregory Temple on the trail of criminal mastermind Henri de Belcamp, a.k.a. John Devil, who plans to use such technology, and the "Grey Men" it produces, to reshape the world. But behind the scenes, another faction is secretly at work: an esoteric secret society of immortals led by the alchemist Joseph Balsamo who also seek Frankenstein's secret... The Shadow of Frankenstein is the first volume in a prodigious Alternate History saga which embraces the works of Mary Shelley, Paul Féval, Alexandre Dumas and others, written by Brian M. Stableford, an acknowledged master of the genre, author of the critically acclaimed The Plurality of Worlds.