MY OLD SWEETHEART
by Susanna Moore
Houghton Mifflin; 211 pages; $12.95
Nearly halfway through this first novel the heroine makes a passing reference to Anna Karenina. Her remark is no accident, for she belongs to a family that is unhappy in ways Tolstoy would understand. Her father, Sheridan Shields, is a doctor who practices in a lush, remote area of Hawaii. He was one of the first Americans allowed into Hiroshima after the Bomb; he left the flattened city with an infant Japanese boy whom he had delivered and an incurable case of moral...