The Lorax by Dr. Seuss
I absolutely love love love this book. I guess as much as any other Dr. Seuss book, but this one in particular, has special meaning to me. It hits right to the heart to know that a children's book like this exists, to focus on such important concepts like environment, ecology, economy, relationships to all our friends on this plant, and even a strong language.
I learned a few great words: gruvulous, snergelly, rippulous, cruffulous.
Here is the video for this book. I don't even know what to say, except that again Dr. Seuss has managed to boggle my mind with his masterful imagination and literations.