AND A VOICE TO SING WITH A Memoir by Joan Baez Summit. 378 pp. $19.95

THERE WAS never any question about the voice -- it was, and is, a remarkable instrument, at once formidable and sweet, capable of stirring an audience or soothing a child. The human being who came with it often seemed a bit much, though -- barefoot and humorless, pompous at times, her famous vibrato fluttering with righteous indignation.

"My growing collection of utterly pure, nearly sacrosanct folk songs was not something to be paid only partial attention to, and neither, apparently, was I," Joan Baez admits, engagingly, in this memoir. "As my repertoire expanded, my rigidity stayed the same. Each song was as desperately serious at the last."

In a year when the market is glutted with synthetic, self-serving, ghost written autobiographies, Joan Baez has -- not surprisingly -- actually sat down, written her own book and tried hard to be honest about her life. The result is very much in keeping with the self-conscious amateurism that informed the folk music movement of the 1960s, and that is a mixed blessing.

There are more than a few passages in this book that are painfully embarrassing. Time and again, Baez commits the most popular autobiographical sin of the 1980s: revelation without insight. She tells all and says nothing. In the name of "honesty," we are forced to endure endless, mindnumbing descriptions of her neuroses -- specially her fear of vomiting (do we really need to know this?) -- and yet, after years of therapy, she seems as puzzled about the causes of her seemingly bottomless well of anguish as we are. Worse, we are subjected to constant, puerile gushings about the fleeting objects of her affection (nearly always younger men; in one instance, a younger woman). The effusions come to a climax, as it were, when backstage at the Live Aid concert, the author spots: "Miami Vice Johnson, whose TV show stands for everything I've spent my life fighting against -- namely, the glorification and justification of violence -- well, he is some charismatic hunk of maleness . . . and what he lacks in depth, he makes up for in clothing." The infatuation continues for several pages as Baez embarrasses herself and us by chasing after the poor fellow and assorted other rock stars. "I realize," she admits, "that I no longer know how to conduct myself around men."

This is sad, and unnecessary. Baez, it seems, is obsessed with the need to convince the public that she isn't as "serious" as her image, that she enjoys having "fun." The irony is, her memoir works best when she is being serious, especially when she is describing people other than herself, and the historic movements she has been part of -- civil rights, antiwar, human rights -- over the past 25 years.

Although Al Capp lampooned her as Joanie Phoanie in L'il Abner during the 1960s, Baez was never a dilettante. She was, in fact, far stronger and more consistent in her beliefs than most of her colleagues in the antiwar movement. She was raised a Quaker and has remained steadfast in her nonviolence. Her willingness to criticize the government of Vietnam for its human rights abuses, even after she suffered through the famous Christmas carpet-bombing of the North in a Hanoi bunker, is perhaps the best example of her clear-eyed sensibility. The chapter in which she describes the bombing is the most memorable in the book. It is a harrowing experience, and Baez even stumbles across a viable insight into her psychiatric self-indulgence: "I wondered about the children who spent their lives ducking bombs. The ones I'd met seemed very stable. Perhaps it was better to have something real to deal with than to conjure up, as I had, symptoms and phobias all of your childhood. Here was the difference I'd thought so often about, between victims of ourselves and victims of circumstances. Me and my years of therapy . . . And here, where the children had always known war, perhaps life was a little more precious."

There are other good things to be found here: a surprisingly bitter portrait of an obnoxious and inconsiderate Bob Dylan; fleeting, dewy-eyed glimpses of Martin Luther King and Lech Walesa. In the end, there is the inescapable feeling that we've spent time with an actual human being, despite the embarrassing attempts at "honesty." We cringe with Baez, and for her, and are moved by the experience. :: Joe Klein is the author of "Woody Guthrie: A Life" and "Payback: Five Marines After Vietnam."