This is a wordless picture book filled with pages of detailed illustrations depicting several mysteries at once.  The setting is a park on a sunny day where a kid’s birthday party is in progress.  All the characters are animals dressed and behaving like humans.  The illustrations comically tell the stories of the progression of the birthday party, a stolen necklace, the baking of the birthday cake and several other sub plots.  There is a group of mischievous monkeys, a tantruming party guest, and some very suspicious-looking rats.  This book could be enjoyed by a wide range of ages since reading is not required and the clues for the various mysteries range from obvious to subtle.  I think it is one that children would pick up again and again to discover some new detail each time.