The sleuths at Botswana's No. 1 Ladies' Detective Agency confront some characteristically poky new dilemmas in the slight, winsome seventh installment of the Alexander McCall Smith series, Blue Shoes and Happiness. A cook has been stealing her employer's food for her fat husband, a doctor is falsifying blood-pressure readings, and a newspaper advice columnist may be running a blackmail racket. Meanwhile, ''traditionally built'' Mma Ramotswe goes on a diet and her colleague Grace Makutsi buys a pair of impractical, pointy-toed shoes. ''Most problems could be diminished by the drinking of tea and the thinking through of things,'' Mma Ramotswe reflects, again demonstrating how common sense, decency, and a hot drink can save the day.