Michael Innes is one of those almost relentlessly-literary mystery writers who are "thick on the ground," as he would say, only in England. In "Sheiks and Adders," his usual hero, Sir John Appleby, the retired head of the London police, is given to what might be called arch ratiocination. He goes to a local fete at Drool Court, for example, merely out of a curiosity to know why Cherry Chitfield's father "was being so intransigent over the detail of a particular piece of miming or charade." He is drawn to the fete "by a sense of a small mystery," which is surely the idlest speculation ever indulged in even by a retired English policeman.

Sir John is witty. He notices that when people dress up at a fancy dress ball, they do it literally, in the sense of upward mobility, choosing costumes of rather exalted rank. Mark Chitfield...