The library is commonly considered to be one of the basic public buildings necessary within any large town or city.

Libraries can be autonomous but many are part of a library system. If they are part of a library system, there is usually a main library somewhere close by, which houses most of the administrative aspects of the system. Smaller libraries in the system are known as branch libraries. These answer to the main library, and rely on it for vital services.

The main function of a library is to stock books which the public may look through, or borrow for a certain amount of time. Libraries also maintain subscriptions to periodicals for people to read. Computers are sometimes provided and these can serve a multitude of purposes, such as searching the library catalogue, or using the Internet.

Materials

Adult Books

Adult books are typically divided into fiction and non-fiction. Fiction is defined as a book whose subject matter is imaginary, whereas non-fiction books refer to actual places, things, or events. Non-fiction is divided into regular, oversized¹, and reference. Reference books must remain inside the library at all times. These books can be looked at by library members, but may not be taken out of the library. All non-fiction books are classified according to the Dewey Decimal System², which divides books up according to subject matter.

Fiction is divided up by genre. Common divisions are regular fiction, westerns, romances, science fiction, short stories and mysteries. Different library systems have different methods of separating these. Some put them all together, while some separate certain genres, like mysteries and science fiction, and put the rest all together. Many libraries also separate out paperbacks, and keep these apart from the hardcover books. Books are shelved alphabetically according to the last name of the author. If more than one author share the same last name, then the first name is also taken into account. As with non-fiction, multiple books by the same author are then alphabetised by title³.

Children's Books

The way children's books are divided is similar to that for adult books. Fiction and non-fiction are organised the same way that adult books are, although there is often an extra section for picture books, which are books containing large illustrations with little or no text.

Periodicals

Generally, each library, whether it is autonomous or a branch library, maintains its own collection of periodicals. New issues are placed out for the public to look at, and older issues are stored, either in their original form, or on microfilm, for research purposes. Different library systems have different policies about lending periodicals. Some systems may allow you to borrow them, and others might not.

Computers

Most libraries now keep their catalogues on computers rather than on cards⁴. Many libraries are now equipped to provide high-speed Internet access from these computers, allowing people to gain access to informational sources outside the walls of the library. These computers can also be equipped with various informational programs on CD-ROM. These vary from serious research tools to educational software for children.

Circulation

Most libraries allow their books to circulate⁵. The lending period varies between systems, ranging from two weeks to two months. Circulation records are stored in a computer database, which means that they can be cross-referenced with the public catalogues, allowing them to show which books have been checked out. For books that are not returned by the due date, most libraries charge a small fine per day.