Mo Willems, award-winning, New York Times best-selling creator of The Pigeon, Knuffle Bunny, and Unlimited Squirrels, presents best friends Elephant Gerald and Piggie. 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. In The Thank You Book!, Piggie wants to thank EVERYONE. But Gerald is worried Piggie will forget someone . . . someone important. Read all of Elephant Gerald and Piggie's adventures!- Today I Will Fly!- My Friend is Sad- I Am Invited to a Party!- There is a Bird on Your Head!- I Love My New Toy!- I Will Surprise My Friend!- Are You Ready to Play Outside?- Watch Me Throw the Ball!- Elephants Cannot Dance!- Pigs Make Me Sneeze!- I Am Going!- Can I Play Too?- We Are in a Book!- I Broke My Trunk!- Should I Share My Ice Cream?- Let's Go for a Drive!- Happy Pig Day!- Listen to My Trumpet!- A Big Guy Took My Ball!- I'm a Frog!- My New Friend is So Fun!- Waiting is Not Easy!- I Will Take a Nap!- I Really Like Slop!- The Thank You Book