The premise of "What's in that tree?" is an old visual riddle - two vertical lines with four circles, that turn out to be a bear in a tree. From there, each successive "animal in a tree" tries to one-up the previous one, avoiding repetition - unless it is to mislead the reader.
This picture book is intended for very young children - playing peek-a-boo is an atavistic delight for any baby or toddler. At the same time, the adult who reads it to their child will find some pleasure in it as well, and the preschooler who starts to read will discover words and creatures that are beyond the classic staple of barnyard animals - not to mention the fun of being in on a joke.