This note deals with (a) the theory of leading inputs, (b) irrigation potential, its development and utilization under successive five years plans, (c) the size and composition of public investment in harnessing various sources of irrigation and their benefits in general terms, (d) major problem-areas of development of irrigation as an input, and finally, (e) a strategy required to address to these problem areas, so that better realization of benefits of public investment in irrigation may be realized.