Dolphin C 369 (1962)
- there has not been a British paperback edition.

Synopsis:

On Thursday, October 17, 1678, a famous London magistrate, Sir Edmund Godfrey, was found dead - strangled and stabbed. Titus Oates, the renegade priest, came forward with evidence that linked the crime with a Popish plot to poison Charles II. A dozen people were brought to trial. Among the suspected were Catherine, the Queen, and Samuel Pepys. Three men were judged guilty and died on the scaffold; later their innocence was proved beyond question. To this day no one knows who killed Sir Edmund Godfrey, though a score of biographers and historians - including Hume, Macaulay, Sir George Sitwell, and Andrew Lang - have tried to solve the riddle. John Dickson Carr, one of the best modern detective story writers and the author of The Life of Sir Arthur Conan Doyle, has attacked the problem with relish, and with an appreciation for both history and the finer points of criminal fiction. He brings the complicated, turbulent case to life and offers an extremely plausible explanation for the mystery that De Quincey called "the finest work of the seventeenth century."