Auguste Dupin, of course, was created by Edgar Allan Poe and used in three stories. And, as you would expect from the title, there is a tie-in to Poe’s “The Facts in the Case of M. Valdemar”.

The conceit of the series, narrated by an American friend of Edgar Allan Poe living in Paris, is that some Poe stories were based on fact but their supernatural aspects added by Poe. Thus, there really was a Valdemar who was hypnotized at the point of death.

The year is sometime between 1845 (when Poe published the above story) and his death in 1849.

Honoré Balzac’s mistress seeks the narrator’s help in protecting a shipment from America containing Valdemar’s last remains. There is a theory among some mesmerists that contact with those remains will extend life.

Valdemar’s daughter needs help protecting them. She’s the protégé of Comte St. Germain. He claims he’s the Comte St. Germain of legend, but Dupin and the narrator aren’t buying it. Dupin thinks St. Germain, who shows up in most of the novels in the series, is starting to believe his own patter. One of his claims is his increasing mesmeric powers as head of the Harmonic Society.

One of the pleasures of the book is Stableford’s exploration of the literary, occult, and scientific milieu of France in the mid-19th century. There was a split between mesmerists who looked upon it purely in material terms as a possible anesthetic or cure for bodily ills and the “spiritual” mesmerists who thought it could provide occult knowledge. The Harmonic Society is in the latter camp.

Dupin notes that the days of the former school are numbered since work is being done on chemical anesthetics already. (There is an amusing scene where an academician is hypnotized while having some teeth removed.)

Stableford makes great use of Edward Bulwer-Lytton’s Zanoni from 1842.

A major theme in the book is the power of suggestion in influencing how people perceive events.

I enjoyed this suspenseful book and kept wondering where it was going to go. ( )