CAST OF SHADOWS

Guilfoile's engrossing debut novel takes a high-concept look at the age-old but still provocative question of nature vs. nurture. The story centers on Chicago fertility doctor Davis Moore, a pioneer in the field of cloning, whose teenage daughter, Anna Kat, is raped and murdered. When no leads pan out, a desperate Moore secretly uses the killer's DNA to clone him, with the unsuspecting aid of a client couple, so that one day he'll be able to identify the killer by his resemblance to the clone. The novel spins out over more than two decades, following the rocky development of the cloned boy, Justin Finn (whose parents know nothing of his potentially problematic DNA), Moore's monitoring of the young man and Moore's own complicated life. Though nominally a thriller, the book's jolts and tension are driven by character rather than plot, with the unpredictability of Moore, Justin and two other characters keeping the reader constantly off balance. Anna Kat's killer remains an active menace and is eerily close to the Finn family, and the novel also offers a nuanced and chillingly believable portrait of a religious zealot and terrorist, Mickey the Gerund, who racks up a lot of abortion clinic bombings and doctor kills over the years. Guilefoile displays a deep interest in his characters (backstories for all abound), and if his plot is a bit of a patchwork, the novel as a whole is rich and involving. Agent, Simon Lipskar. 7-city author tour. (Mar.)