S.M. MATHUR retired from the Geological Survey of India in 1977 and thereafter was appointed Emeritus Scientist at the University of Saugar (1978–1984) by the Council of Scientific and Industrial Research. He is also a past President of the Geology and Geography Section of the Indian Science Congress. He has been a president of the Indian Association of Sedimentologists and the Editor of its journal. His researches in some aspects of sedimentology and stratigraphy have received international recognition and have also been incorporated in geology textbooks and glossaries published abroad. He has made important contributions to the field of economic geology, and is considered an authority on the geology of Indian diamonds, having worked as a consultant for over a decade to the diamond giant DeBeers. Among his other books, he is the author of the highly acclaimed Physical Geology of India (English and Hindi, nine editions), Guide to Field Geology, Rupa Book of Geology Quiz and Concise Glossary of Geology. Besides, he has published more than 130 scientific and research papers in national and international journals. He is also deeply interested in the English language and has written books on some aspects of good English. As a hobby he creates and collects jokes, and has published two collections.