"Books and periodicals" refers to publications including books and periodicals. A book refers to a collection of bound words and images, which can be novels, essays, poems, academic works and other types of books. Publications refer to publications published continuously or irregularly within a certain period of time, such as magazines, newspapers and periodicals. Publications can be divided into internal publications (for internal personnel to read) and public publications (for public distribution) according to their distribution objects and forms.