Recently, I picked up “Letters to a Young Poet,” by Rainer Maria Rilke, to read for the second time. I had fallen in love with the book when I was 17 and daydreamed about meeting the author, whom I imagined to be a kind, prophetic soul. Realizing now how little I knew about Rilke’s life, I Googled him.

I wish I hadn’t. A line from John Berryman’s poem “Dream Song 3” popped up: “Rilke was a jerk.” I clicked on a link to a Washington Post review of “Life of a Poet,” a biography of Rilke by Ralph Freedman. “On page after page it portrays one of the most repugnant human beings in literary history,” the critic Michael Dirda wrote.

How could the kind prophet whose lengthy passages I’d copied into my teenage diary be a selfish, sycophantic, womanizing rat?

“One unexpected development of becoming a writer is meeting literary heroes,” Justin Torres, author of “We the Animals,” told me. “Unfortunately, sometimes they turn out to be asses, or they hit on you.” The novelist Jennifer Haigh agreed; she once had a famous poet invite her to sit on his lap. Haigh finds reading biographies equally disquieting; though she loved Blake Bailey’s biography of Richard Yates, she was saddened to find out how deeply troubled he was. “Learning about a writer’s life changes your relationship with him. It sort of destroys the fantasy,” she said. Laurie Halse Anderson, the author of “Speak,” also feels that biographies can make authors lose their luster. “A book is like sausage,” she told me. “You love the end product, but you don’t really want to know how it’s made.”