Can there be too much of a good thing when it comes to biography? If there is someone Amanda Vaill did not interview, if there is a document she overlooked, if there is an archive or other source of information she could not access, it is news to me. I have to second Terry Teachout's claim, "I can't imagine a better book about Robbins ever being written."

Of course there will be other books because, to quote Mr. Teachout again, "Jerome Robbins is the great subject of American theatrical biography." Others may demur, but certainly this magnificent choreographer (the term does not do justice to his many talents) is a great subject.

Even for those who have already read earlier biographies by Greg Lawrence and Deborah Jowitt, there are rewards, because Ms. Vaill has used Robbins's own articulate writings (many of them unpublished) to provide an intimate portrait that bridges the gap between autobiography and biography.

Every reviewer can only come to "Somewhere: The Life of Jerome Robbins" (Broadway, 675 pages, $40) with a partial knowledge of Robbins. I know him mainly from work on musicals like "On the Town," "West Side Story," and "Fiddler on the Roof." Others know Robbins for his ballets and his collaborations with great artists such as Leonard Bernstein. Still others (an angry cohort) can't get over Robbins's naming names at his House Un-American Activities Committee hearing.

Ms. Vaill slights none of these aspects of Robbins's career. If she is resolutely sympathetic toward Robbins, taking the edge off the caustic man who appears in other biographies, she not so much rebuts the work of others as simply presents what she obviously regards as a fuller portrait, a dramatic, incremental revelation of the kind we expect in novels of a high order.

I suppose a reader less than committed to the arts, less than attuned to the politics of the New York stage during much of the 20th century, could weary of the detail that informs Ms. Vaill's narrative. Jerome Robbins deserves a lyrical biography, the equivalent of a dance with the reader, and Ms. Vaill obliges. If a better biography is ever written about Robbins, it will have catapulted off Ms. Vaill's strong work.

But quite aside from the biographer's superb handling of Robbins's major achievements, the story of how he transformed himself from Jerome Wilson Rabinowitz to Jerome Robbins, how he negotiated his love life as a gay man who also loved women — and countless other aspects of his art and life — what entranced me was the discovery of how literate Robbins was. At a very early age he was reading Faulkner (always a good sign in my book) and the other greats. Robbins himself wrote very well and had an ear for music that often helped him to coalesce dance steps and movements into a form that resulted in extraordinary rapport with collaborators like Bernstein.

Lest you think Ms. Vaill knows everything, I hasten to add that she cannot say if the Bernstein/Robbins partnership ever segued into the sexual. A few murky references in Robbins's diaries suggest as much, but they are not definitive. And Ms. Vaill does not push the matter. It is a matter of tact — biographer's tact — not to go beyond the evidence, or beyond (in this case) how Robbins or Bernstein may ultimately have understood their relationship.

Beyond tact, there is Ms. Vaill's knack for finding the nub. Every biographer writing for a general audience has to supply a certain amount of background. How much, for example, should readers be told about the Group Theatre or the Actors Studio, which contributed significantly to Robbins's artistic development? Some readers, like me, already know quite a bit and will chafe at boilerplate. Here is how Ms. Vaill treats the work of Elia Kazan and Robert Lewis, two founders of the Actors Studio: "The cornerstones of Lewis and Kazan's teaching were Stanislavsky's twin principles of intention, or the importance of one's character's objective in a given scene, and work on oneself, or technique." This pithy statement neatly avoids the pitfalls of saying too much or too little. Believe me, there is a considerable margin of error. A less able biographer might introduce Actors Studio by referring to "the Method," or to the prickly personalities involved. But Ms. Vaill wants to show what Robbins got out of it. Even a reader well versed in the ins and outs of theatrical history will never bored by this fresh, concise explanation of a well-known institution.

Ms. Vaill's biography does not so much supplant previous efforts as provide a broader and deeper context that can be used to assess them. And I take her own acknowledgment of previous biographers at face value: She is indeed "indebted" to them. How else could she write with such precision, knowing where her score needs a soft pedal or crescendo?

There can be too much of a good thing in biography. Countless biographies have foundered on precisely the grounds Ms. Vaill stands on. Congested with too much detail, with too much good fortune in the way of access and archival sources, the biographer cannot resist parading how much she knows. Ms. Vaill, who once upon a time was a book editor and surely dealt with baggy monster biographies, knows what I mean all too well. But it is the rare biographer, let alone editor, who is capable of acting on her own acumen and producing such an exquisitely polished performance. ( )