Animal opposite pairs like quite rabbit and loud lion, heavy hippo and light butterfly, and more. Not only are the illustrations incredible, like pretty much everything else by Horacek, but the pop-ups add an extra element of fun! The pictures are bright and full page, and the text is simple and to the point. One super awesome thing about this book is that Horacek uses some common animals, and some not so common animals. This helps children to identify all sorts of wildlife! YES!