Brother Cadfael (One Corpse Too Many, A Morbid Taste for Bones) returns in another 12th-century mystery--as stylishly authentic, though not quite as darkly inventive, as his previous three. It's July 30, 1139 A.D.--time for the start of the annual St. Peter's Fair, which benefits Brother Cadfael's Benedictine monastery at Shrewsbury. This year, however, the Shrewsbury townsfolk are protesting their own meager share of the fair revenues; and on the eve of the fair there's an altercation between young townsman Philip Corviser and a visiting merchant, Thomas of Bristol. So, when Thomas turns up in the river a few hours later, stabbed to death, Philip is the obvious suspect. Brother C., however, is more generally suspicious--especially when Thomas' barge is ransacked, his strongbox stolen, his coffin tampered with. Someone is obviously looking for something! Furthermore, Thomas' beauteous niece Emma appears to be nursing some secret. Eventually, then: two more deaths follow, Emma is kidnapped by the villain, and the murder motive is revealed to have historical resonances. With colorful, convincing details on the workings of a medieval fair--a graceful and informative, if not particularly mysterious, case for Peters' engaging, herb-gardening monk.