Influence - The Psychology of Persuasion by Cialdini.

http://www.amazon.com/Influence-Psychology-Persuasion-Busine...

The 22 Immutable Laws of Marketing - Violate Them at Your Own Risk!

http://www.amazon.com/22-Immutable-Laws-Marketing-Violate/dp...

Don't Make Me Think: A Common Sense Approach to We Usability, by Steve Krug:

http://www.amazon.com/Dont-Make-Me-Think-Usability/dp/032134...

Information Architecture for the World Wide Web: Designing Large Scale Web Sites, by Paul Rosenfeld and Peter Morville:

http://www.amazon.com/Information-Architecture-World-Wide-We...

Why We Buy: The Science of Shopping, by Paco Underhill

http://www.amazon.com/Why-We-Buy-Shopping-Updated-Internet/d...

And at least one Jakob Nielsen Usability book.

I am not an IA expert at all, but I have read the following book and learned a lot.

http://www.amazon.com/Information-Architecture-World-Wide-We...