It's Rex's tenth birthday, and it's time to party! Molly Idle, Caldecott Honor-winning author-illustrator, returns with a new story to celebrate everyone's favorite dinosaur. Rex cordially invites you and all of his friends to celebrate a milestone birthday, so remember to greet the guest of honor at the door with an enthusiastic "happy birthday," share party favors with the other attendees, and best of all, enjoy some cake and games! When it's time to leave, don't forget to thank the host for a wonderful time and make sure to extend the invitation when it's time to celebrate your birthday.