This unauthorized biography is part riveting empire-building chronicle, part tiresome litany of sexcapades. Gaines has trod much of this territory before in Simply Halston (1991); Churcher is a former Wall Street Journal reporter. Born to a relatively affluent Bronx family, Klein took a job with a Seventh Avenue coat manufacturer, married a local girl, had a baby, and moved to Queens. But when the president of Bonwit Teller fell for a line of Calvin-designed coats and suits, all that changed. Bonwit's hyped him, and other stores lined up to get in on the act. Klein shed his wife and, in the 70's, remade himself into a regular on the Studio 54 and Fire Island scenes, launching a string of affairs with men and women. His daughter was kidnapped but released unharmed. Blue jean sales careened off the charts, helped by those ``Nothing comes between me and my Calvins'' ads featuring Brooke Shields. Klein went on to further success with both underwear and his fragrance, Obsession. As the world around him was decimated by AIDS, Klein edged out of the sex-and-drugs fast lane, marrying Kelly Rector, a design assistant in his studio. Ironically, the machinations of the Klein empire—the advertising coups, the disastrous decisions (i.e., the selection of the first Klein fragrance, which was universally disliked), the high-strung temperaments, the titanic personality clashes—make for far more scintillating reading than the exhaustive attempts to exhume every detail of the designer's sexual history. Occasional excessive biographic license (``A chill ran up Calvin's spine'') subtracts credibility. In all: part solid business reporting, part gratuitous heavy breathing. (First printing of 100,000)