[rramadass]

I think anybody who wants to understand Functional Programming should start with Lambda Calculus.

I highly recommend An Introduction to Functional Programming Through Lambda Calculus by Greg Michaelson.

You can then see how to express Functional Techniques in your language of choice (i.e. one you already know well eg; Functional Programming in C++ by Ivan Cukic) before learning a new Functional Language. This is to avoid the confusion in syntax/semantic expression of unfamiliar concepts which is a bit too much for a beginning student to handle simultaneously.