Here's the list, based on January 1999 to date (the length of time our library system has used its current vendor):
1. John Adams by David McCullough (57)
2. It's Not About the Bike: My Journey Back to Life by Lance Armstrong (55)
3. The Color of Water: A Black Man's Tribute to His White Mother by James McBride (52)
4. The Glass Castle: A Memoir by Jeannette Walls (49)
(tie) A Heartbreaking Work of Staggering Genius by Dave Eggers (49)
6. Dreams from My Father: A Story of Race and Inheritance by Barack Obama (38)
7. Traveling Mercies: Some Thoughts on Faith by Anne Lamott (37)
8. Galileo's Daughter: A Historical Memoir of Science, Faith, and Love by Dava Sobel (36)
9. Population - 485: Meeting Your Neighbors One Siren at a Time by Michael Perry (35)
(tie) The Prize Winner of Defiance, Ohio: How My Mother Raise 10 Kids on 25 Words or Less by Terry Ryan (35)The checkouts include when our copies were loaned to other libraries, but they do not show when our readers got the same titles through interlibrary loan. I assume the two balance out, i. e. that our copies have gone to other libraries as much as other libraries' copies have come into our library.
I am obviously not deleting these books.
I'd be interested in learning what the top circulating biographies are in your library, too.