Gamadge, expert bibliophile, again turns criminologist when his curiosity is aroused over a succession of coincidences involving the presumed discovery of a rare Chaucerian item. The ""long arm"" has a long stretching, good guesses take the place of reasoning, and violent death plus blackmail eventually frees the victim and disposes of the criminals. A lot of money changes hands and the evil doers get away with it -- but ultimately pay with their lives. Better while reading than in retrospect.