I have read every book he has written starting in my teens. His works are largely fiction, but the material is very interesting.
He is one of the most controversial writers of our time. He even appeared on an early David Letterman show in the 1980’s.
Wikipedia’s page on him is a good place to start. The Painted Bird, his famous novel is also a good place to begin.

http://en.wikipedia.org/wiki/Jerzy_Kosinski