The note discusses: (a) various income concepts such as GNP, GDP, National Income, Private Income, Personal Income, and Personal Disposable Income, and highlights their differences as well as differences between real and nominal incomes; (b) various economic units and circular flow of income among them; (c) various approaches to the measurement of income like production, income, and expenditure approaches; (d) shortcomings of national income as a measurement of economic welfare; and (e) provides comparable time series data on decadeable basis on all the pertinent variables.