The Glimpses of the Moon (1977)
The plot reminds me of nothing more than Tom Sharpe's outrageously lewd comic fantasies, of which the two best are the brilliant Riotous Assembly and Indecent Exposure. In Crispin's book, there are two nymphomaniacs, one with a lover named John Thomas; a structure called the Pisser; and several other examples of madcap and coarse humour. While the humour is often very funny, the murder plot is poor. Obscure references are made to the murder for the first fifty pages. There is little thought involved in the solution of the crime, and clues are concealed from the reader, before Fen reveals the solution, padded by continual remarks from the Major and the Rector. The solution depends on a re-working of gimmicks from Agatha Christie's Hercule Poirot's Christmas (1938) and a shrewd stylistic quote from Chesterton.
Note several similarities to Gladys Mitchell: the title is reminiscent of The Rising of the Moon (1945), of which Crispin wrote rave reviews (one wonders why); elements of the solution are borrowed from The Mystery of a Butcher's Shop (1929); the fete and the red herring of the subnormal suspect come from the Saltmarsh Murders (1932); and the gory business with the corpse is a common occurrence in classic Mitchell.