The Wanderer in Unknown Realms — John Connolly

Books alter men, and men, in their turn, alter worlds. Soter is a man who has been haunted by World War I. But when he's sent to investigate the disappearance of Lionel Maudling, the owner of a grand country house whose heir may be accused for his death, he encounters a home that will lead him to nightmares he could have never imagined. Maudling's estate houses countless books of every sorthistories, dramas, scientific treatises. But none seems to offer Soter any hint to Maudling's whereabouts, until he's led to an arcane London bookseller where the reclusive scholar made his last purchase. What Soter finds at the end of a twisted maze of clues is a book like no other, with a legacy that will put everything he knows in danger An inventive horror novella from internationally bestselling author John Connolly, this is a story of madness, of obsession, and of books' power to change the world.