I think one of the most intricate and deep books ever writen would have to be The Sea Wold by Jack London. The charictor evolution is slow, but the majority of the book is based around the psychological conflicts between the main charictor and the captain.
I don't want to ruin anything, but let's just say that our main charictor is put aboard this ship simply as a special guest for the captain. Who's joys lie not in the sea or in commanding his ship, but in the truth about. . . Well . . . Life, the universe, and everything. :D
Of course the following conversations are some of the deepest and most exquisite samples of writing ever captured on the page. I would definitely recommend anyone that's looking for a deep read.