They should understand the needs of the library's users. Cost is another factor to be considered in the selection of material. Trained librarians catalogue and classify. They are well tutored in the rules and methods they use. A catalogue is the record of all the materials in the library.
People use it to check whether the library has what they want.
Classification is a way of coding all items in the library so that they can be arranged according to their subject matter. Once catalogued, the material goes through various coding stages. Jackets and pockets are then put on the books. Library assistants are responsible for the routine work in a library. They issue books and other resources, replace returned items in the correct place on the shelves for retrieval and help people find information and books.