In the same book as 'The Black Lizard', this is a more conventional thriller with the protagonist being a writer of detective stories which he considers are of two kinds - those where the crime and its commission are all that matter and those where the motives and psychological background come to the fore, the sort of which the narrator is one. He becomes involved with a beautiful young wife of an older successful businessman because she is being threatened by a lover from her past who is also a writer of detective stories but of the former kind. She is greatly disturbed by receiving letter which describe her home
life in intimate and exact detail with the stated threat of revenge for her having jilted her lover. The latter has been very successful but has always been a misanthrope and recluse with his wife being the contact with the outside world. Efforts to find him are unsuccesful and the threat to kill her husband is carried out which leaves the narrator even more determined to bring the killer to justice - he has also by now become emotionally and physically involved with the widow. Excellent plotting brings the story to an unexpected conclusion though the ending is logically presented and completely realistic. I found this the more satisfying of the two tales possibly because it is much closer to the usual detective stories being written in Britain and the USA at the same time and later.