Der Club Dumas by Arturo Pérez-Reverte

A jaded rare-book detective is hired to authenticate a mysterious manuscript fragment and becomes drawn into a parallel hunt for a legendary 17th-century occult treatise, a pursuit that sends him through Europe into a web of forgeries, obsessive bibliophiles and a secretive, conspiratorial network; as he follows clues in old books and encounters seduction, betrayal and ambiguous morality, the investigation blurs the line between scholarship and superstition and turns into a tense, witty literary thriller that probes the power of texts and the passions they inspire.

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