Truth and Beauty: A Friendship by Ann Patchett (2004)

Memoir in which Patchett writes about her longtime friendship with poet and author Lucy Grealy. They became friends at the Iowa Writers' Workshop and supported each other through friends, lovers, books, and more. But, Grealy, who had more than a little self-destructive streak, eventually became quite hard to be friends with, and this book is an interesting exploration of friendship, depression, and along the way, writing.