- Dadabhai Naoroji, known as the "Grand Old Man of India", was a prominent early nationalist leader, economist, and politician. - His 'drain of wealth' theory argued that Britain was exporting wealth from India in the form of salaries, pensions, profits, and other payments, for which India received no equivalent economic return. This economic exploitation was seen as the primary cause of India's poverty. - His influential book 'Poverty and Un- British Rule in India', published in 1901, detailed this theory and provided statistical data to support his arguments.