My only real beef with this book is the way it short-changes Gertie in the title. The book is all about Manny and Gertie, who spend every Saturday battling imaginary monsters together all around town. Until, in the midst of some of their imaginings in the park, they notice the way litter is impacting the whole park (and especially the turtles in the pond). So they set their efforts into battling the real monsters: litter bugs. As others in the park notice their efforts, they pitch end to lend a hand and everyone benefits. A little cheesy perhaps, but a good message. I just don’t know why Gertie gets no credit?