A librarian is a professional who works in a library, providing people with access to information, as well as social and technical programmes and teaching in information literacy, among other things.
The job of the librarian has evolved significantly throughout time, with the twentieth century in particular bringing a slew of new media and technology to bear on the profession. From the oldest libraries in the ancient world to today's information superhighway, there have always been custodians and disseminators of the knowledge contained in data storage facilities. According to the kind of library, the librarian's area of expertise, and the duties required to keep collections in good condition and make them accessible to its users, roles and responsibilities differ significantly.
Education for librarianship has evolved throughout time in response to the changing functions of librarians.