First of all, we should analyze the theme of a book to determine which category it belongs to, and then give it a classification number according to the rules of multiple classification and imitation classification. If you want to put it on the shelves, you should give it a category number, a call number, an author number and so on according to the rules formulated by the library itself. This work is very complicated. For details, please refer to Ma Zhanghua's Information Organization.