The most borrowed fiction, nonfiction, ebooks, teen fiction, and juvenile books (top 20 books in each category) from the San Francisco Library in 2021. Based on data provided by the San Francisco Public Library, The Chronicle compiled a list of the most borrowed books in 2021. The list includes national bestsellers, like "The Vanishing Half," "The Midnight Library" and former President Barack Obama's memoir "A Promised Land." But it also includes titles by Bay Area-based authors, like Bonnie Tsui's "Why We Swim" and a collection of essays by local writers, "The End of the Golden Gate: Writers on Loving And, Sometimes, Leaving San Francisco."