The dancer Carolyn Brown begins her lengthy and ultimately rewarding “Chance and Circumstance: Twenty Years with Cage and Cunningham” (Knopf, 612 pages, $37.50) with as unwieldy an opening 100 pages as could be encountered in any memoir. The book starts with her describing her final week of dancing with the Cunningham Company, during a tour to Paris in 1972, but after two paragraphs this plot thread is dropped, not to emerge until the book’s conclusion. She tells us on page 4 that Mr. Cunningham was born a month prior to Margot Fonteyn, but any possible relevance of this factoid is not disclosed until page 77, when Ms. Brown begins to discuss her reverence for the Royal Ballet’s prima ballerina.

Part of the reason that the facts and competing storylines initially fly off the page in centrifugal fashion is that Ms. Brown has aimed for an ambitious and slightly genre-bending work. It is part personal memoir, part anecdotal exercise in dance history, part formal and even encyclopedic review of John Cage’s and Merce Cunningham’s philosophies and careers. The book is largely the product of diaries and letters she wrote during her dancing years, but she also frequently quotes (and sometimes rebuts) critics and historians, consulting the published as well as conversational memories of Cage, Mr. Cunningham, and Ms. Brown’s fellow Cunningham performers.

Passionately as she admired the work of Cage and Mr. Cunningham, Ms. Brown was not and is not a true believer, bringing home the truth that a creative artist’s most notable interpreters are often those who confront the creator with some resistance. Ms. Brown’s mother danced with the Denishawn Company, and Ms. Brown began to dance at age 3, but she had no intention as a young adult of making dance her life’s work, preferring to pursue a career as a writer. The progressive and apostate aesthetic and philosophical tenets of Cage were, in retrospect, what gave her the intellectual motivation to dance. Yet Ms. Brown is frank about what she saw as the rifts in both his and Mr. Cunningham’s personalities — most of all Mr. Cunningham’s difficulty in communicating honestly and directly with his performers.

Like many critics and spectators, she objects mightily to the decibel level at which Cage allowed his compositions to be performed (she thinks he ceded too much autonomy to the musicians), not only torturing dancers and audience members in the process but running real auditory risks. “If we knew as little about our bodies as they seem to know about the physical and psychological effects of sound we’d be considered RANK AMATEURS,” she wrote to her then-husband, experimental composer Earle Brown, in 1967.

Ms. Brown writes in an accessible manner but has wisely not refrained from expatiating on aesthetic topics. She describes in depth all the Cunningham works he made during her 20 years with him and is frank about the ones she loved and those she considered minor. She disagreed with Mr. Cunningham’s incessant insistence that his steps had no significance beyond the palpable reality of movement. She saw and describes a wide range of themes, subtexts, and moods that he deliberately evoked in his work, without, of course, making them programmatic.

For most of Ms. Brown’s two decades with Mr. Cunningham and his troupe, performances were few and far between, salary virtually nonexistent, audiences often skeletal, and critical reaction frequently uncomprehending. Delayed aesthetic justice is not necessarily justice denied, but it’s quite clear that by the time recognition began to arrive for Mr. Cunningham, Cage, and their dancers, all had been irrevocably depleted by their years of adversity. (Part of the reason for the falling out among Cage, Mr. Cunningham, and Robert Rauschenberg, who designed for the company for many years, was Mr. Rauschenberg’s amazingly prodigal success as a painter.)

Again and again, the U.S. State Department refused to provide any funding for the Cunningham Company’s international tours, which nevertheless became triumphant affirmations of the vitality of American culture. Although today’s professional dance companies are hardly lavishly funded, Ms. Brown seems to feel that today’s dancers are somewhat spoiled and complacent. She is certainly justified in asserting that the privations she endured would be unimaginable to most dancers in the leading professional companies today.

Once it settles into a narrative, Ms. Brown’s memoir is both entertaining and informative, the wealth of detail supplied not only revealing but relevant. Perhaps her most important achievement in this book is that she makes the reader care. One takes vicarious satisfaction when Mr. Cunningham, Cage, as well as Ms. Brown and her fellow dancers receive some of the recognition that was their due. There is no question that painful as their sacrifices were, she and they could not and would not have lived their lives any other way.