Belly Button Book!

Sandra Boynton does what Boynton does: she finds one absurd premise — a beach full of bare-bellied hippos obsessed with their navels — and commits to it completely with rhymes and illustrations that are irresistible for babies and quietly hilarious for the adults reading aloud. The die-cut cover shaped like a navel is the kind of tactile detail that makes board books memorable. Continuous print since 2005 with multiple new editions speaks for itself. The honest caveat is that this is pure entertainment; it is not teaching colors or numbers or letters. But at the board book stage, a book that makes a baby and a parent laugh together has done exactly what it should. Boynton's best work, and this sits comfortably in that category.