Enter the title directly. Book retrieval is a convenient device to find books in the library. Enter the name directly into the title to fill in. A library is an institution that collects, sorts out and collects books and materials for people to read and refer to. As early as 3000 BC, libraries appeared. It has the functions of preserving human cultural heritage, developing information resources and participating in social education. Library is the external storage and selective transmission mechanism of social memory. In other words, the library is the memory device and diffusion device of social knowledge, information and culture.