An unusually appealing book with a number of surefire features, not least of which are the eponymous monsters ``standing on the wall'' who, one by one, ``accidentally fall'' in the classic tradition—as revealed by opening a broad flap on each spread. Each stumpy, grinning monster is individualized by its cheery garments and unique appendages (also, one has a yoyo and one a book); as those on the ground grow more numerous, they commiserate amiably with one another and eventually realize—as alert readers will already have done—that one of their number has been mischievously pushing the rest. After he gets his just deserts, young readers are sure to go back to the beginning to check out the preceding byplay once again; fortunately, the sturdy pages and binding should withstand plenty of rereadings. (Picture book. 3-7)