Sara Krulwich/The New York Times

Philip Roth has a new biographer: Blake Bailey, the author of highly regarded biographies of Richard Yates and John Cheever. Mr. Bailey said on Wednesday that in June he and Mr. Roth signed a collaboration agreement guaranteeing him unlimited access to Mr. Roth’s archives and correspondence, and help in encouraging friends to cooperate, and that he had already spent several marathon sessions interviewing the 79-year-old novelist.

The project will take him 8 to 10 years to complete, he estimated, and he plans shortly to send out a proposal to book publishers.

Mr. Bailey is actually the second writer to begin a life of Mr. Roth, the author of 26 novels (several highly autobiographical) and two volumes of memoirs, “Patrimony: A True Story” and “The Facts: A Novelist’s Autobiography.” In 2004, Mr. Roth appointed Ross Miller, a professor at the University of Connecticut and nephew of the late playwright Arthur Miller, as his biographer.

That arrangement was abandoned by mutual consent in 2009, according to Mr. Roth’s agent, Andrew Wylie. Mr. Miller remains the editor of the nine-volume Library of America edition of Mr. Roth’s writings.

Mr. Bailey said he approached Mr. Roth in the spring, after finishing his latest book, a biography of Charles Jackson, who wrote “The Lost Week-End,” but had to undergo a lengthy vetting process before securing his approval. According to Mr. Bailey, the first thing Mr. Roth wanted to know was what qualified a gentile from Oklahoma to write his biography. “I pointed out that I’m not an aging bisexual alcoholic with an ancient Puritan lineage and I still managed to write a biography of John Cheever,” he said.