Public libraries exist in many countries across 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, and other special libraries in that their mandate is to serve the general public's information needs rather than the needs of a particular school, institution, or research population. Public libraries also provide free services such as preschool story times to encourage early literacy, quiet study and work areas for students and professionals, or book clubs to encourage appreciation of literature in adults. Public libraries typically allow users to "borrow" books and other materials, i.e., take off the premises temporarily; they also have non-circulating reference collections and provide computer and Internet access to patrons.