Who wrote a book describing the theory of economic drain of India during British rule?

Answer 1

Dadabhai Naoroji
In 1867, Dadabhai Naoroji put forward the 'drain of wealth' theory in which he stated that the Britain was completely draining India. He mentioned this theory in his book Poverty and Un-British Rule in India. Further in his book , he stated the loss of 200-300 million pounds of revenue to Britain.