The general secretary of the Spanish Communist Party is murdered. Pepe Carvalho, gourmet private detective, seems the ideal man to track down the killer. Unfortunately, the job requires a trip to Madrid -- an inhospitable city whose gastronomic and sexual agendas are inevitably thorougly inferior to those of Barcelona. This, the best-known title in the Pepe Carvalho series, features everything that is wonderful about the books: sex, politics and a most vivid sense of contemporary Spain.  (SPN402, $14.95)