(Image from here.)
Then we picked up a few Elephant and Piggie Books at the library (by Mo Willems, author of Knuffle Bunny: A Cautionary Tale and Don't Let the Pigeon Drive the Bus!).
The Elephant and Piggie books are hilarious (especially to a four year old), simple enough for him to get most of the words, exciting, and best of all they are helping him want to read! Oh, and did I mention that most of the books also have a good message about being nice to friends/helping others?! That is what I call a great book!
Go check some out!