Some of mine are sorted by subject, some by author, some by technique and the rest are just on the shelf willy nilly. Some day I'm going to alphabetize the willy nillies by author or title. I keep small notebooks in my purse with the titles willy nilly but separated by first letter of the title. I recently got rid of a whole lot of books so my lists have to be redone. I really want to put them on a spread sheet.