The sixth book in the Inspector Morse series is, indeed, a riddle. The author, Colin Dexter, also had a passion for crossword puzzles, and he's created here an intricate puzzle that ultimately borders on the convoluted. The case involves an Oxford don named Browne-Smith, a bachelor, who goes mysteriously missing after being lured to London by the promise of exotic sex. Shortly thereafter, a body is pulled from a river. The corpse is wearing a suit that belonged to Browne-Smith, but it's missing its head, arms and legs. Is it really Browne-Smith?
The case falls to Inspector Morse of Oxford Homicide, assisted, as always, by his trusty sergeant, Lewis. Morse is a confirmed bachelor who loves the challenge of his job, along with his beer and attractive women. As the investigation proceeds, Morse discovers that bitter rivalries played out in the hallowed halls of Oxford academia, leading in turn, to some very complicated maneuverings. Soon, other bodies are falling and sorting it all out is going to be a very challenging task, even for someone as brilliant as Inspector Morse.
This book was first published in 1983, and is an excellent example of the "puzzle" mysteries that were so popular in British crime fiction at that time. As a practical matter, there's no way that the reader can figure out who done it; you can only hang on and go along for the ride. It's always fun to watch Morse in action, but as is the case in a few of these books, the plot gets a little too complex for its own good and there are maybe one or two totally unanticipated and unnecessary twists at the end. But fans of the series are sure to enjoy it.