The Five Laws of Library Science is a text in which S. R. Ranganathan set out five principles governing the organization and use of library collections. Alongside this work, Ranganathan developed the Colon Classification, a faceted classification system, and together these two contributions formed the core of his output as a library scientist.

Ranganathan was born in Sirkazhi in 1892, during the period of the British Raj, and received his education at Hindu High School, Matanhail, and subsequently at the University of Madras. He worked as a mathematician, a librarian, a university teacher, and a writer. He used both English and Tamil in his work. His training as a mathematician ran alongside his career as a librarian and library scientist, and he came to be widely known as the Father of Library Science in India.

Ranganathan received the Padma Shri in literature and education and the Margaret Mann Citation, and was inducted into the Library Hall of Fame. These recognitions spanned the fields of librarianship and education, reflecting the range of roles — librarian, teacher, writer — that he occupied across his career as an Indian citizen.

He died in Bengaluru on 27 September 1972. The reach of his work is marked in a concrete and continuing way in India, where his birthday is observed each year as National Librarian Day, a formal annual recognition tied directly to the date of his birth.