THIS SPRIGHTLY BIOGRAPHY of Andre Previn, conductor of the Pittsburgh Symphony and one of music's most mulit-faceted talents, opens with a revealing sketch of the 16-year-old Previn sheepishly showing up in an ill-fitting rented tuxedo to play the piano for a glamorous party at Mary Pickford's estate, "Hollywood's Mount Olympus." After the party, movie mogul Lousi B. Mayer offered Previn a ride home in his limousine. Lighting a cigar, Mayer remarked that he'd recently heard "what's-his-name . . . Heifetz," at the Hollywood Bowl. "The guy'll never make it with the kind of stuff he plays," quipped Mayer. Stumbling for words, Heifetz was as friend of his parents, Previn asked whether Heifetz wasn't at least "a sort of success" since he'd played at the Hollywood Bowl. "Lots of people play the Bowl," scoffed Mayer, "But you don't see him in the movies do you? If the guy was big, he'd be in the movies."

The remarkable contempt for artistic integrity revealed by that remark raises the question at the heart of this biography: why did it take Previn another 16 years to abandon Hollywood and pursue the career in serious music he had desired and been trained for since childhood? As early as the age of 5, after a Furtwangler concert in Berlin, Previn knew what he wanted to do; he was so overwhelmed by Furtwangler's "cataclysmic" conducting that he went home and threw up. Yet for years after his family migrated to California from Nazi Germany, Previn remained in Hollywood as arranger, composer and pianist, playing at the Hollywood Bowl with what he calls "horrendous regularity." When Dick Cavett asked him why in 1978, he explained: "I have stayed because I had a great deal of fun and because the work, in a cheap way, was glamorous and thrilling. I suppose I should also mention greed and stupidity."

As Martin Bookspan and Ross Yockey (authors of Zubin: The Zubin Mehta Story) explain it, Previn's 20-year double career as movie composer/arranger (Bad Day at Black Rock, Kismet, Gigi, My Fair Lady, to name a few) and jazz pianist offered "the path of least resistance and economic security." Previn's superb ear and improvisational acuity created a constant demand for his talents and numerous accolades, including four Academy Awards.

The break with Hollywood is most dramatically and wittily described, as is often the case with this book, by Previn himself. The scenario was a movie producer's office in the mid '60s, with Previn, who had been agonozing over whether to change over to serious music, waiting for comment to change over to serious music, waiting for comment on his newest film proposal: "He said -- and these were his exact words -- 'Stick around kid while I read this over.' So I stuck around and watched him. There he was, this great man in a great studio, sitting behind a desk you could have staged the Ice Follies on and I suddenly realized: My God, he's moving his lips as he reads! . . . All at once it came to me that I was desperatley unhappy, working on music I didn't believe in, trying to impress my musical values on a man who moves his lips when he reads."

Previn excused himself, stood up, and walked out on Hollywood, with enough time in the business day to contact manager Ronald Wilford, who put him on a distinctly unglamorous road to places like Kalamazoo and Lekhart, "the civic auditoria of America's heartland," where he learned basic repertoire on the road and landed a contract with the Houston Symphony in 1966. "One day I just looked around and he was gone," says Shelly Manne. "To Houston."

But conservative Houston's sour reaction to Previn's predilections for contemporary music and Mia Farrow (while Previn was still married to his second wife) made his stay in Houston a brief one. In 1968, he became conductor of the London Symphony Orchestra, a post ideally suited to his anglophilic sensibility, where he remained longer and played to larger audiences than any previous conductor. A decade later, he moved back to America, where, despite his avowal to never "inflict my 'sound' on an orchestra," he has already imbued the heavy, teutonic Pittsburg Symphony with the lithe, transparent, rhythmically propulsive sound that has become his trademark.

But there is another story here, one less dramatic but perhaps more significant, and one that veteran record reviewer Martin Bookspan is specially qualified to write. The real breakthrough for Previn came with a series of mid-'60s recordings intricately negotiated by Schuyler Chapin of Columbia and Roger Hall of RCA, both of whom were convinced of Previn's potential as a major conductor. Two of these recordings, the Shostakovich Fifth and William Walton First symphonies, both with the LSO, boasted performances of such microscopic clarity and blazing power that Previn simply had to be taken seriously, pop-music taint and all. Furthermore, the LSO's "immediate affinity" with Previn during the recording sessions was surely an important precursor to Previn's tenure in London. This book traces the history of these and other recording sessions with authoritative detail, making it clear that the 200 records Previn had made since 1965 constitute a major achievement and legacy.

The authors are less persuasive and detailed on Previn's private life. Indeed, they complain that whenever they asked Previn about his failed marriages (to Betty Bennett, Dory Previn, and Mia Farrow) and notorious affairs, he would either answer, "Not me. Brick wall," or offer a "clinically detached" analysis. Thus the fetching outlines of Previn's tempestuous private life are offered here, but the authors do not indulge in the gossipy nuances characteristic of such books as Joan Peyser's "psychobiography" of Boulez.

Given the unusual richness of Previn's life, the outlines are quite enough to make this an engaging if not especially probing biography. As the authors point out, Previn is "the only person in world who can so vividly recount anecdotes about Lenny Bruce on the one hand and Sir William Walton on the other," and this book is crammed full of splendid anecdotes from both worlds.

as for Previn himself, he remains an enigma, a man whose life is full of scandal and glitter but whose manner on the podium is unremittingly sober and businesslike. Critics such as former LSO secretary Harold Lawrence say that Previn is "afraid of the big gesture," reluctant to "grit his teeth and lunge into the music with his heart and soul." But to those of us who admire the sobriety of conductors such as Reiner, Szell, and Boulez, Previn's self-effacing commitment to the music at hand is a considerable strength. As he himself says, in one of the many memorable Previn quotes in this book, "By leaping six feet into the air, you do not get them to play the sforzando any louder."