In the grand tradition of the great sleuths brought to life by Sir Arthur Conan Doyle comes another master. John Thorndyke is cerebral, meticulous, British, and underestimated. When Thorndyke's assistant, Dr. Jervis, gets a mysterious summons to ride to an undisclosed location in a sealed-off carriage, there are signs of a dangerous plot aloof. Patiently, logically, using all his prowess for jurisprudence, Thorndyke maneuvers his way through a labyrinth of clues: broken glass, an upside down picture, a veiled woman, a box of candles. Others have declared the case "impossible," and Jervis, too, has his doubts. Will the mystery at Number 31 prove in the end to be even Thorndyke proof? - Back cover.