The terms “black money” or kala dhan are often confusingly used to refer to both black income and black wealth. It is crucial to make a clear distinction between black income, a flow concept, and black wealth, which may be held in the form of currency, a stock concept. Among other notable studies in the area are the Wanchoo Committee Report of 1971 and the 1992 book, Black Income in India, by the late Suraj Bhan Gupta of the Delhi School of Economics.
The work under review seems to bear a strong stamp of his previous work.
Kumar seems to have had some strong disagreements with the analysis that was carried out in this work, and he later came out with his book, The Black Economy in India (1999). The NIPFP study is possibly the most comprehensive and authentic treatment of the subject to date.