Monsoon being complex climatologically phe­nomenon a number of concepts and theories have been put forth by meteorologists to explain its ori­gin.

Initially it was considered to be a simple atmos­pheric circulation caused by the seasonal unequal heating and cooling of the land and water bodies. But as researches progressed due to greater availability of upper air data its complexity increased.

So much so that last word has yet to be said on the origin and behaviour of this complex wind system whose accu­rate prediction is still eluding the scientists. G.B. Cressey has rightly observed, “it has been well said that although every school boy understands the In­dian monsoon, the official meteorological depart­ment is still in doubt as regards its origin.” Following is an account of some of the views throwing light on the origin of the Indian monsoon.