Shiyali Ramamrita Ranganathan was a mathematician and librarian from India. He is considered to be the father of library science, documentation, and information science in India and is widely known throughout the rest of the world for his fundamental thinking in the field. His birthday is observed every year as the National Library Day in India. Ranganathan, born on 12 August 1892 to Ramamrita, in Tanjore in British-ruled India. After two decades of serving as librarian at Madras – a post he had intended to keep until his retirement, Ranganathan retired from his position after conflicts with a new university vice-chancellor became intolerable. At the age of 54, he submitted his resignation and, after a brief bout with depression, accepted a professorship in library science at Banaras Hindu University in Varanasi, his last formal academic position, in August 1945.