===About the Book=== When Linda Fairstein describes the route Alexandra Cooper takes from the district attorney's office to NYPD headquarters, you know she's walked that way many times herself. "I took the shortcut over to One Police Plaza, cutting behind the Metropolitan Correctional Center and alongside the staggeringly expensive new federal courthouse, which made our digs, complete with oversized rodents and roaches that obviously thrived on Combat, look like judicial facilities in some third world country." Like her fictional counterpart, Fairstein is a Manhattan assistant district attorney in charge of a sex-crimes unit. As she did in ''Final Jeopardy'' and ''Likely to Die'', Fairstein mires her somewhat unlikely heroine (a beautiful 35-year-old blond with an Ivy League education, a house in Martha's Vineyard, and an affection for betting on quiz shows at cop bars) in a wealth of procedural detail. The "cold hit" of the title, for example, refers to a computer match between DNA samples from a recent rape case with evidence from an older crime. With her trusty cop sidekicks Mike Chapman (who eats everything in sight and drops wisecracks like they're crumbs) and Mercer Wallace (who is a big fellow and can take a bullet meant for Alex without flinching), Cooper is working on two major cases--a serial rapist who has suddenly decided to come out of hiding and a couple of murders linked to the nasty underground world of fine-art sales. But she also has time to give her fellow sex-crime prosecutors advice on how to handle everything from a man shooting video up women's skirts at a ''Star Trek'' convention to a guy who takes his love for racehorses well past the legal limits. Once again, Fairstein has produced a story whose entertainment value is very high. ''--Dick Adler''