BONNIE RAITT: JUST IN THE NICK OF TIME

BONNIE RAITT: JUST IN THE NICK OF TIME Mark Bego (Birch Lane Press, $22.50) This unauthorized biography of the seasoned country-blues rocker amounts to little more than a dry valentine copied and collated on a Xerox machine. With an almost total reliance on previously published quotes, Bego, the author of 26 celebrity biographies, offers a standard portrait of Raitt as a tomboy who grew up resentful that her famous dad (singer John Raitt) wasn't around enough to be a real father, and with her pacifist, Quaker upbringing, gravitated toward music as a way of changing the world. We see the singer as musically principled, sincerely dedicated to political causes, and generally bighearted, especially toward forgotten blues pioneers. But the real person never really emerges -- instead of a biography, it's an unedited, track-by-track breakdown of her albums by a man who can't adequately describe what he hears, can't remember what he wrote (one quote is repeated verbatim in two places), and whose empty-headed idea of snappy chapter endings includes ''Word was spreading that Bonnie had the blues. She had 'em bad -- and that was good!'' A mess. D