S.R.S. Varadhan's entered the Indian Statistical Institute (ISI), Calcutta, as a graduate student in 1959. His first paper appeared in Sankhyá, the Indian Journal of Statistics in 1962. Together with his fellow students V.S. Varadarajan, R. Ranga Rao and K.R. Parthasarathy, Varadhan began the study of probability on topological groups and on Hilbert spaces, and was soon noticed internationally. He understood then the strong connections between...