An adopted child turns 18, learns the shocking story of her real parents’ identity, and determines to reclaim her natural mother. A mild-mannered man vows revenge on the woman who killed his onlychild. No, neither of these premises is terribly original or inherently profound; but P. D. James, whose richly textured, probingly psychological approach is familiar to followers of her Dalglieshdetective series, laces up these two plot strands with crisp and gentle dexterity, resisting every melodramatic cliché that a lesser writer would lurch into. The young identity-seeker is Philippa Palfrey,who remembers nothing of her life before age eight–when she was adopted by unflappable sociologist Maurice and his shaky second wife Hilda, a compulsive cook. And, though Philippa has grown into awildly sophisticated and intellectually sharp young lady (an aspiring writer), she’s oddly detached from all feeling, aware of some great lack. So at age 18 she demands and receives her birthcertificate, and after just one day of inquiries, she knows the truth: ten years ago, her father raped a little girl, her mother then killed the girl (to stop her screaming), and both went to prison–where herfather died. But Philippa is only momentarily deflected: she insists on contacting her real mother–who’s about to be paroled–and invites her to spend her first months out with Philippa in a Londonflat. And while all this is happening, retired clerk Norman Scase, father of the girl killed by Philippa’s mother, is preparing to take revenge–for his daughter who was raped and killed, for his wifewho died of grief/cancer. The parallel scenes are beautifully, subtly balanced: Philippa’s frustrating, seedy search for an affordable two-room London flat; Norman’s sad selling of his house to gainfunds for his revenge mission. And by the time that Norman has quietly, shrewdly tracked down his reclusive target and chosen his modus operandi, Philippa has come to love her pleasant, attractive,…