P. D. Eastman was an author and illustrator who created many children's books, including Are You My Mother?; Go, Dog. Go!; and The Best Nest. Trained at the National Academy of Design, he published his first Beginner Book, Sam and the Firefly, in 1958. Since then, his books have sold more than 50 million copies, and he has become one of the most beloved children's book authors in the world.