Both in the library and on the home lot, all adult’s and children’s books were cleaned up by clicking the “Clean Up Books” interaction on the bookshelf, but all of the toddler’s books were ignored.
Community ManagerI have this same issue. I tried repairing my game. I tried deleting everything and starting with a totally fresh installation. I've been playing the Sims since 2001. The only books available for purchase are the books my sims already own. If my sim doesn't own a book in a particular category, that category is not available in the purchase menu. The missing books are not grey out. They don't appear at all and the category the belong to does not appear.
The Sims Team