He is the son of Sir Sita Ram, a zamindar/educator/barrister/politician from Meerut.
He was a Reader in History at Aligarh Muslim University, Aligarh before joining the newly established Centre for Historical Studies, Jawaharlal Nehru University, New Delhi as a professor and a co-founder.
He belongs to the marxist group of Indian historians. As a member of the Indian History Congress, he supports secular historiography of India in the medieval and early modern periods. Communalists opposed historians such as Ram Sharan Sharma, Satish Chandra, Romila Thapar, Bipan Chandra, Arjun Dev, Irfan Habib and Barun De whose text books had long been used in schools. More recently in 2004 their textbooks were reintroduced in the national curriculum after a hiatus of six years when the books had been removed for political reasons.
- (ed. and tr.), Balmakandnamah. English and Persian Letters of a King-Maker of the 18th century, (by Balmakand Mehta and Sayyid Abdullah Khan), (London: Asia Publishing House, 1972)
- Marwar Under Jaswant Singh (1658-1678): Jodhpur Hukumat Ri Bahi, (Meerut: Meenakshi Prakashan, 1976) (co-edited with G.D. Sharma and Raghubir Sinh)
- The 18th century in India: Its Economy and the Role of the Marathas, the Jats, the Sikhs and the Afghans, (S.G. Deuskar Lecture for the CSSSC), (Calcutta: K.P. Bagchi & Co., 1986)
- (ed.) Essays in Medieval Indian Economic History, (Indian History Congress Golden Jubilee Year Publication Series, v.3) (New Delhi: Munshiram Manoharlal, 1987)
- (ed.) The Indian Ocean: Explorations in History, Commerce and Politics, (New Delhi: Sage, 1987)
- The Indian Ocean and its Islands: Strategic, Scientific and Historical Perspectives, (New Delhi: Sage, 1993) (co-edited with B.Arunachalam)
- Report of the Committee to review the Scheme of the Civil Services Examination, (New Delhi: UPSC, 1989)
- Medieval India: Society, the Jagirdari Crisis, and the Village, (Delhi: Macmillan, 1992)
- Historiography, Religion and State in Medieval India (New Delhi: Har Anand, 1996)
- Medieval India: From Sultanat to the Mughals, (New Delhi: Har Anand Publications, 1997)
- Parties and Politics at the Mughal Court, 1707-1740, (New Delhi: OUP, 2003; 4th Edition)
- Mughal Religious Policies, the Rajputs and the Deccan, (Delhi: Vikas Publishing House, 2003)
- (ed.) Studies in Archaeology and History: (Commemoration Volume of Professor S. Nurul Hasan), (Rampur: Rampur RazaLibrary, 2003)
- Religion, State and Society in Medieval India: Collected Works of Saiyyid Nurul Hasan, (New Delhi: OUP, 2005)
- Essays on Medieval Indian History (New Delhi: OUP, 2005)
- History of Medieval India (800-1700) (2007)
- Social Change and Development in Medieval Indian History, (New Delhi: Har Anand Publications, 2008)
- State, Pluralism and the Indian Historical Tradition, (New Delhi: OUP, 2009)