I wanted to limit this to fiction, to novel-length writing, and that also threw me for a loop a few times. I realized I couldn't include Walden or Up From Slavery. Likewise O'Henry, Tillie Olsen, and Truman Capote, whose writings are short stories -- at least, of those I've read. I love Tolstoy's short stories, but couldn't make it through War and Peace if you paid me, so he's out. I've allowed it in a few instances (Kipling, Bradbury) when the collection has a common theme or thread that unifies the stories.