Leo Lionni is a legend in my book. He wrote more than 40 books (including four Caldecott Honor books) and was an inspiration and friend to Eric Carle.
Here's a few of my favorites:
A Color of His Own
Fish is Fish
The Biggest House in the World
Whether you're a little small black fish who wants to be bigger and better, a chameleon with identity issues, a fish with dreams too big to understand, or a snail without a grip on what's too much - be who you are. It's a beautiful thing. Be proud of yourself and what you can do.