A public library (also called circulating library) is a library which is accessible by the public and is generally funded from public sources (such as tax moneys) and may be operated by civil servants. Taxing bodies for public libraries may be at any level from local to national central government level.

Public libraries exist in most nations of the world and are often considered an essential part of having an educated and literate population. Public libraries are distinct from research libraries, school libraries, or other special libraries in that their mandate is to serve the public's information needs generally (rather than serve a particular school, institution, or research population). Public libraries typically are lending libraries, allowing users to take books and other materials off the premises; they also have non-circulating reference collections. Public libraries typically focus on popular materials such as popular fiction and movies, as well as educational and nonfiction materials of interest to the general public; Internet access is also often offered.

Services offered

In addition to print books and periodicals, most public libraries today have a wide array of other media including music CDs, computer software, movies on video tape, and DVD, as well as facilities to access the Internet and inter-library reservations. Some public libraries use outside services, such as OverDrive, Inc. or OCLC's NetLibrary, to provide patrons with downloadable eBooks, audiobooks, music, and video. Readers advisory is a fundamental public library service that involves suggesting fiction and nonfiction titles (often called "readalikes"). Public libraries may also provide other services, such as community meeting rooms, storytelling for infants, toddlers, and children, or after-school programs. In person and on-line programs for homework help, language learning and other community service programs are common offerings. One of the most popular programs offered in public libraries are summer reading programs for children, families, and adults. In rural areas, the local public library may have, in addition to its main branch, a mobile library service, consisting of one or more buses furnished as a small public library, serving the countryside according to a regular schedule.

Public libraries also provide materials for children that include books, videos and DVDs, music CDs, and other materials (both fiction and nonfiction), often housed in a special section. Child oriented websites with on-line educational games and programs specifically designed for younger library users are becoming increasingly common. Public libraries may also provide services for other particular groups, such as large print or Braille materials, young adult literature and other materials for teenagers, or materials in other than the national language.