This is one overjoyed puppy!"I am happy," declares the pup. "I'm SO happy I…sing on a swing, swing as I sing, head in the sky, like a butterfly." The pup chases after bubbles, dances, does somersaults, and walks on clouds! Our furry protagonist grabs the paw of a kitty, whom readers may remember from Rosen and Starling's I Am Angry (2022). They're both joined by a squirrel from the creators' I Am Hungry (2023), and they "walk on air, wind in [their] hair." These pals do many outlandish things, from rolling down mountains and dancing in fountains to racing cars "all the way to the stars" and putting on elaborate talent shows. That's how happy this puppy is! The friends are happy enough to play all day. Rosen follows his previous explorations of strong emotions aimed at the very young with a strong depiction of joy that the youngest listeners will understand and identify with. Starling's mixed-media illustrations of wide-eyed animals exhibiting emotions and using their imaginations are once again an excellent fit with the simple text, written in a bouncy, exuberant verse. As in previous installments, Rosen's note to adults encourages them to learn and play with youngsters as they read the book with their grown-ups.A happy hound's verse, sure to inspire smiles. (Picture book. 2-6)