The call number is not printed on the book. It is numbered by the library to facilitate the management of books and readers' borrowing. It is written (or printed) on a label and then affixed to the spine of the book.

The uppercase English letters at the beginning of the call number indicate the library’s classification number for the books (both ends of each bookshelf will be marked with the category of the books on the shelf, such as C representing ancient Chinese literary works, etc.), followed by The number should be the year of publication of the book or the number in the book of this type.

The call numbers are very sequential. Generally, the books on the bookshelf are arranged in the order of the call numbers. Therefore, it is easier for readers to check the call numbers before borrowing books to find the corresponding books.

Extended information:

Categories of call numbers:

Mainly include 4 types: classification/author call number, classification/book title call number, Classification/chronological call number, classification/cataloging call number.

Their structures are roughly the same, and they are composed of two basic parts. One part is the classification number, listed on the upper row; the other part is the book number, that is, the author number, book title number, book publication year number, and the book number. Cataloging sequence numbers for category books are listed on the line below the category number. For a few books, the call number only consists of the two basic parts mentioned above. However, for most books, in order to make the call number specific, the following symbols must be appended according to the specific situation:

① The book title number is appended only after the author number to distinguish different authors of the same category. book.

②The edition number is added to the next line of the author number or book title number to distinguish different versions of the same work.

③The volume number or part number is added to the next line of the author number and other four numbers to distinguish different volumes of multiple books and different copies of the same book.

In addition, when necessary, a language number (to distinguish foreign books), a document type identifier (such as a reference book identifier) ??or a special collection number must be added to the classification number. Most libraries in China use classification/author order call numbers and classification/book cataloging order call numbers.

Baidu Encyclopedia-Call Number