Edited by Joseph Lewis French, this collection of 9 riddle stories includes "The Mysterious Card" and its sequel by Cleveland Moffett, "The Oblong Box" by Poe, "A Terribly Strange Bed" by Wilkie Collins, "The Lost Room" by Fitz-James O'Brien and others selected as masterful examples of the genre by the editor. He says in the forward:
"A distinguished American writer of fiction said to me lately: 'Did you ever think of the vital American way we live? We are always going after mental gymnastics.' Now the mystery story is mental gymnastics. ... The stories of this collection cover a wide range and are the choice of reading in several literatures."