Ingenious to the last, Agatha Christie kept back one Poirot and one Miss Marple story, each written some 30 years ago, for publication after her death. The date of its vintage, of course, doesn't matter in the least, since Christieland is as socially frozen and lacking in specifically dating detail as the world of [P. G.] Wodehouse or [Ivy] Compton-Burnett. It's all as ordered, stiff and unlikely as an everlasting flower: from gay, happy young couples and solid professional oldsters to servants who can't spell and gardeners who can't even pronounce the names of plants properly. Here, murders are by definition a trifle insane; good men tend to attract bad women; psychiatrists have just been heard of, though Miss Marple prefers to call them ironically 'mental specialists'; and the phrase for a girl who enjoys a bit of a fling (gosh, the idiom is catching) is 'man mad'.

Sleeping...