British author Peter Ackroyd, a one-man encyclopedia of British history, language and culture, has written 31 books of fiction, biography, cultural criticism and poetry, many of them prizewinners. I suspect Ackroyd of writing books in his sleep — or maybe he doesn’t sleep.

His latest, The Casebook of Victor Frankenstein, is a brooding, melancholy variation on the theme of Mary Shelley’s classic novel. It will enhance your knowledge of the original version, and it may give you nightmares.

Students of the 19th-century novel Frankenstein, or, The Modern Prometheus know that it had its genesis in the summer of 1816, the cold and rainy “year without a summer” caused by a volcanic eruption. Mary Godwin (all of 18 years old), her soon-to-be-husband Percy Bysshe Shelley, Lord Byron, and Byron’s physician John Polidori took a summer holiday in a Lake Geneva villa.

Trapped indoors by the filthy weather, they amused themselves by reading German ghost stories. Eventually Byron persuaded members of the group to create their own (Polidori would later turn one of his stories into The Vampyre, one of the first vampire novels).

Ackroyd recrafts this story by inserting Victor Frankenstein, the scientist who creates the monster, into the lives of this group. He takes numerous liberties with the Shelleys’ biographies, but he creditably portrays the pressures (some self-imposed) the Shelleys were facing in their young lives: disinheritance; out-of-wedlock pregnancy; infant death.

A grieving Victor, who has come to England after the death of a loved one, embodies the belief of the age: that science can make anything possible. He buys dead bodies from London’s “resurrectionists” — grave robbers who dig up freshly interred cadavers and sell them to researchers. A tubercular would-be medical student dies and Victor obtains the body, he shoots it through with electricity, and the monster is born:

There is a fear of the dead coming alive, but this was more frightful: in a moment the body in front of me had gone through all the stages of decomposition before being reclaimed and restored to life… His eyes had opened, but where before they had been of a blue-green hue they were now grey. The body itself had not been deformed in any way; it was as compact and as muscular as before, but it was of a different texture. It looked like it had been baked. The face still had the remnants of beauty but was now utterly changed in hue. All… this was the work of an instant.

As in the Mary Shelley version, things go bad, very bad. At first the monster revels in the miracle of his resurrection and wishes nothing more than the company of his creator; spurned, he wreaks terror, violence and murder. Victor flees, first across the English countryside, then to Geneva, to escape his creation.

The Casebook of Victor Frankenstein tries to cram too much into its 353 pages; the lives of some very august personages are bent to the will of the plot. But the voice of the monster — ecstatic at his rebirth, then aghast at what he has become, distills both the 19th century’s wonderment at the potential of science, and the 21st century’s horror at its more diabolical outcomes.

After reading this, check out The Original Frankenstein (Vintage, $14), a new edition edited by Charles E. Robinson. This volume presents two previously unpublished versions of Mary Shelley’s novel — one as she originally wrote it; another indicating Percy Shelley’s contributions. A tale told again and again, it still casts a spell.