By Mo Willems, Author & Illustrator. Gerald is careful. Piggie is not. Piggie cannot help smiling. Gerald can. Gerald worries so that Piggie does not have to. Gerald and Piggie are best friends. Today, I Will Fly! is the funny introduction to the characters. Piggie is determined to fly. But Gerald the elephant knows that’s impossible–isn’t it? For ages 3 and up.