I thought this book was excellent.
From Publishers Weekly: "The eighth novel tries unsuccessfully to tie a surfeit of tabloid dramas into a single plot. A mystery as well as a chaste romance, the narrative includes surrogate motherhood, separation of twins at birth, duckling-to-swan plastic surgery, serial murders, extrasensory powers and canine heroics, to name a few threads. Left as a foundling at a chapel in France, Chase Carlton, a clairvoyant in his mid-30s, lives in California where the police and FBI hire him to track serial killers. He sees the announcement of the death of movie mogul Victor Chase Kincaid, whom he deduces must have been his brother. Aided by self-induced amnesia, he impersonates his (recovered) twin and insinuates himself into the life of the widow, whom he suspects of murder and for whom he develops complicated feelings. With a supporting cast of cardboard characters whose intertwining relationships require a flow chart to track, Stone builds her story with a series of portentous melodramatic moments that have little impact on the reader, who will be well ahead of the characters in figuring out what to expect next. Only the question of Kincaid's death holds the reader to the end, and that is more a question of how than who in this overwritten and overambitious novel." Copyright 1994 Reed Business Information, Inc.
Chase discovers he has (had) a twin brother and the circumstances of his death are suspicious. He takes his brother's place to try and discover the truth.