Historical evidence suggests that libraries existed in ancient Egypt as early as 1250 BC. Although the nature, purpose and characteristics of these libraries were different from today's libraries, the main objective, the collection, organization and processing of information resources for easier and better access, has remained at the core of librarianship.

In the past librarians played the role of keepers of information resources with responsibility for providing conditional access to the collections for specific users. Modern librarians have a variety of roles, ranging from collection development and management including archiving and preservation, to organization and processing of information resources, managing access to information resources, providing information services of different kinds, designing and providing user education and training services, and a variety of management activities including technology and project management. Given such a variety of tasks, the job of a librarian in today's world has become very complex and demanding. University education programmes and a variety of in-service and continuing education programmes train and equip library and information professionals in accomplishing their tasks effectively and efficiently, and moreover professionally.

The nature of the job and role of librarians have changed over the centuries, and drastically so in recent years with the introduction of information and communication technologies in different areas of librarianship. The profession has been influenced and modified by a variety of socio-political changes, and developments of human civilization in general.

While the core of the profession has remained the same – dealing with information and providing services to users – the terminology used to define and redefine the job of a librarian, as well as to reflect the nature and complexities of the profession, has changed. The most commonly used terms to define the profession include: library science, library and information science, information service management, information management and more recently knowledge management. Several researchers have defined and compared the scope and connotations of these terms. S. R. Ranganathan, in the early 1930s, introduced the term ‘library science’ by proposing five fundamental laws governing the ethos of the profession. The introduction of computers and communication technologies in different aspects of the profession has focused attention on its scientific nature, but there are arguments for its humanistic nature too; librarianship has also been defined as a social science since it deals with human beings and society at large.