Always Crescendo : Leonard Bernstein's meteoric rise seemed to last all his life--but so did his sense of being torn: Was he a composer or a performer? Highbrow or popular? Gay or straight? : LEONARD BERNSTEIN, By Humphrey Burton (Doubleday: $25, 581 pp.)

We all knew Lenny well. He lived in public. He made music accessible. He was both a showman and a man of self-absorbed reflection. He analyzed himself endlessly to friends, to journalists, in his music, in his writings. He talked and talked, and taught and taught, to television audiences, to concert audiences, to students. He partied and partied, living to the hilt the life of a major celebrity. He entertained presidents, kings and emperors; he seduced young writers and musicians. People talked about him. He was biographied, in sober German manner, in American fanzine style and, in a controversial 1987 psychobiography by Joan Peyser, in sensationalistic style. Memoirs have been written by family and friends over the years.

But we are going to get to know him a lot better. There are at the moment, 3 1/2 years after his death, 21 books about Bernstein currently in progress. All will have to contend, however, with Humphrey Burton's biography. Burton, a British television producer who made concert videos of Bernstein for 20 years, was allowed by the Bernstein heirs exclusive access to the Bernstein archives, including his correspondence. The result is the most detailed report, by far, of Bernstein's life.

In a disclaimer, Burton says that despite the invaluable support from the Bernstein family he wrote only what he wanted. That's probably true. The biography does not seemed whitewashed. But Burton is a close friend of the family--Bernstein played organ at his wedding--and could clearly be trusted. Not a practiced writer, Burton has very little voice in the book. The writing is dispassionate, flat, seldom judgmental. But the style is also a relief, with none of the motherly clucking over Bernstein's sexual excesses as Peyser does.

Burton simply tells a story. He appears to rely more on the Bernstein archives and the correspondence than on his own investigations. The facts, however, are engrossing. He sees Bernstein's life in great dramatic arches, which are surely oversimplifications--one of Bernstein's great attractions was the sheer complexity of his life--but that life did have its share of genuine theater, full of public incident and inner conflict. First there was the provincial youth, the boy genius growing up in Boston suburbs with Russian immigrant parents, his father a pragmatic salesman of beauty supplies and devoted student of the Torah.

Though Bernstein had to fight his father to enter a life of music, there seems never much question that he was destined for it. At an early age he already mesmerized everyone he came in contact with, from piano teachers (one, Helen Coates, became his devoted personal secretary for the rest of her very long life) to the siblings and friends he organized into impromptu kid summer stock opera companies.

At Harvard, Bernstein became sophisticated fast and made a mark early. By the time he graduated he was already part of Aaron Copland's circle. He made New York friends, such as Adolph Green and Betty Comden, with whom he would soon write hit Broadway musicals. He was taken under the wing of Serge Koussevitzky at Tanglewood, and his career rise was meteoric. With Koussevitzky and Copland behind him, he was soon conducting everywhere. In 1943, at age 25, he made his famous Carnegie Hall debut, conducting the New York Philharmonic in a Sunday afternoon national broadcast as a last-minute substitute for Bruno Walter, garnering a front page New York Times review--and he was famous. His first symphony, the "Jeremiah," was an instant success the next year. It all kept happening faster and faster, and he just got more and more famous. By the summer of 1957, he went from one of the most celebrated Broadway openings of modern history, "West Side Story," which looked as if it could pave the way to a new kind of American musical theater, to assuming the helm of the New York Philharmonic a few weeks later.

Bernstein's great ascent was accompanied by much self-doubt, however. Burton briefly develops the theme of duality in Bernstein's character (as much as any theme can be developed in such a purely expository approach). Bernstein was constantly torn. Should he be composer or performer? If performer, was he conductor or pianist? Whether composer or performer, was his place in high art or in popular art? Was he teacher or entertainer? Was he gay or straight?