Gerald the Elephant and Piggie are best friends who help each other out. In My Friend Is Sad , Piggie is perplexed to find Gerald feeling low. Piggie dons a variety of costumes—cowboy, clown, robot—in an attempt to cheer him up. Nothing seems to work until Piggie returns as herself. Gerald is overjoyed and explains to Piggie how sad he was because she missed so much excitement. This funny look at friendship and communication is repeated in There Is a Bird on Your Head! when a small bird alights on Gerald’s head, much to his chagrin. Looking to Piggie for advice and sympathy, he gets a play-by-play instead. First there’s a second bird, and then, “They are making a nest!” Finally, “You have three eggs on your head.” When frustrated Gerald explodes in anger, Piggie calmly suggests that Gerald use his words and simply ask the birds to leave. He does, and they do, only to relocate on Piggie’s head. These humorous episodes are illustrated with Mo Willems’ friendly cartoon-like style and pastel hues, complete with dialogue bubbles that convey Gerald and Piggie’s words and emotions. (Ages 4–7)

When Gerald the Elephant is sad, Piggie is determined cheer him up, but finds after many tries that it only takes the simplest thing to change Gerald's mood.