Robert Craft in 1962. (Ernst Haas/Getty Images)

Robert Craft, a writer and classical conductor who spent many years in the company of Igor Stravinsky, producing books about the composer’s life and recordings of his musical works, died Nov. 10 in Gulf Stream, Fla. He was 92.

He had prostate cancer and a history of heart ailments, said a niece, Kristin Crawford.

Mr. Craft was an aspiring conductor when in 1948 he met Stravinsky, often regarded as the pre-eminent classical composer of the 20th century. Within a year, he moved to Los Angeles to live with Stravinsky and his wife.

He then spent more than two decades, in the words of Time magazine, as Stravinsky’s “rehearsal conductor, aide, intellectual catalyst, amanuensis and surrogate son.”

Mr. Craft helped the aging Russian-born composer write music in a new style and adapt to life in the United States. As Stravinsky’s constant companion, Mr. Craft was an intimate witness to what he called “the most interesting life of the 20th century.”

Robert Craft in 1988. (Frans Schellekens/Redferns)

He worked with Stravinsky on seven books, then later produced another with Stravinsky’s widow, Vera. The joint productions were considered groundbreaking at the time, offering insight into the composer’s imaginative world, as well as views of his glittering social life amid such notable figures as writers T.S. Eliot, Graham Greene, Aldous Huxley and filmmaker Ingmar Bergman.

Mr. Craft published other collaborations with Stravinsky, including diaries, conversations and commentary on music and other topics. After the composer’s death in 1971 at age 88, Mr. Craft wrote “Stravinsky: Chronicle of a Friendship, 1948-1971.”

Reviewing the book for the New Republic in 1972, composer Ned Rorem wrote of Mr. Craft: “He proves again that he is not only compassionate and sometimes wickedly funny, but the most readable and intelligent living writer on music.”

Others were not as generous. Stravinsky’s former manager, Lillian Libman, wrote in a 1972 book that many of the comments attributed to Stravinsky were the invention of Mr. Craft.

British musicologist Stephen Walsh charged in a 2006 biography of Stravinsky that Mr. Craft’s accounts were “riddled with bias, error, supposition and falsehood.”

In 2013, Mr. Craft wrote that he believed Stravinsky had several homosexual affairs in his 20s and 30s, but other scholars said there was no evidence for those claims.

Mr. Craft did admit that he “put the words together” on the page in Stravinsky’s voice, but he defended his reputation — and Stravinsky’s — with blistering, point-by-point rebuttals.

“Only two people know anything about Stravinsky,” he said in 1972. “Only Mrs. Stravinsky and I know. Nobody else can come in now and say what happened.”

Robert Lawson Craft was born Oct. 20, 1923, in Kingston, N.Y. His father was a real estate broker.

He showed a precocious talent in music and by 12 was studying musical scores and hoping to meet Stravinsky. He studied at Columbia University and the Juilliard School in New York and worked as a research assistant for composer Arnold Schoenberg.

While serving in the Army during World War II, Mr. Craft attempted suicide, he wrote in his 2002 memoir, “An Improbable Life.” After his discharge, he returned to Juilliard to study conducting and composition, graduating in 1946.

He then embarked on his career as a conductor, founding a chamber society in New York. When he couldn’t find a copy of the score of Stravinsky’s 1920 composition “Symphonies of Wind Instruments,” he wrote directly to the composer. A correspondence ensued, and Mr. Craft first met Stravinsky in March 1948 at a hotel in Washington to discuss an upcoming concert. Mr. Craft persuaded Stravinsky to conduct without payment.

Stravinsky then invited Mr. Craft to contribute to the English-language libretto of the opera “The Rake’s Progress,” and in short order the two found each other indispensable.

Stravinsky, whose revolutionary works “The Firebird,” “Petrushka” and “The Rite of Spring” were all written before 1915, learned about modern forms of composition from Mr. Craft. They worked together every day, and Stravinsky continued to turn out new works throughout the 1960s.

Mr. Craft helped the composer with his English and often read to him at night. For years, Mr. Craft lived in the Stravinskys’ house with no steady income, except from occasional jobs as a conductor or writer.

“In many ways, I was closer to him than his wife, because music was our language,” Mr. Craft said in 1972. “When I first met him, he was living in a refugee world. He valued me because I was young and his first real touch with America. Stravinsky made a cultural switch. He began eating hamburgers on tours and staying in motels.”

After Stravinsky’s death, Mr. Craft published several volumes of the composer’s correspondence and wrote widely on music and other subjects, including philosophy, literature and even the television sitcom “Mary Hartman, Mary Hartman.” He published several volumes of essays.

In the 1970s, Mr. Craft married Rita Christiansen, Stravinsky’s Danish-born nurse. The marriage ended in divorce. Their son, Robert Alexander Craft, lives in Copenhagen.

Other survivors include Mr. Craft’s wife of 22 years, Alva Rodriquez Minoff of Gulf Stream, Fla.; a sister, Phyllis Craft Crawford of New Paltz, N.Y.; and two stepchildren.

Stravinsky’s two children from his first marriage were somewhat estranged from their father and later carried on a long legal battle with Vera Stravinsky, who died in 1982. The composer’s son, Soulima Stravinsky, a former piano instructor at the University of Illinois, was on icy terms with Mr. Craft and disputed some of the details in his books.

The relationship between Mr. Craft and the Stravinskys defied convention and is unique in recent cultural history. Stravinsky himself called the menage a “trio con brio.” Yet few doubted Mr. Craft when he described their bond as a deep and abiding form of love.

“While Craft may sometimes be Stravinsky’s advocate, he is never his surrogate,” composer Allen Shawn wrote in the Atlantic in 1998. “These are two separate artists who, for complex reasons, needed each other.”