His book, 'Secularism at Bay: Uzbekistan at the turn of century', first published in January 2005, was an instant hit. An autobiographical work, it deals in detail about how secularism has been threatened since the 1990s, particularly in Eurasia, by various factors, including market economy and religio-political fanaticism.
An inspiring teacher, De taught at the universities of Oxford, Duke, Sydney, Paris, Milan, and Tokyo. At home, he taught at the universities of Calcutta and Burdwan and the Indian Institute of Management, Calcutta.
Born in a Brahmo family in Kolkata on October 30, 1932, De studied at the Presidency College and the Oxford University. "He was a rare historian who was equally responsible to his students and towards his research work. His death is a huge loss," said Suranjan Das, historian and vice chancellor of Calcutta University, who is also a former student of De.