A dog is a dog … isn’t it? In this circular story, categorization and labels aren’t that straightforward. “A dog is a dog, / whether it’s naughty … / … or nice, / whether it suns on the beach, / or glides on the ice. / A dog is a dog, if it’s skinny or fat. / A dog is a dog, unless it’s a … / CAT!” On the final page turn in that rhyming sequence, the plump brown and white dog of the previous scenes is shown unzipping its dog costume and emerging as a cat. Or is it a cat? The unveiling of a series of costumed creatures continues, much like revealing a set of nesting dolls. Simple enough for very young children, the well-paced text contains some pleasingly surprising revelations (who’d have expected squid?), while the uncluttered, flat illustrations lend an old-fashioned sensibility. (Ages 2–5)