My three-year-old likes this book a lot. He doesn't quite "get" the concept of recycling that's the solution to the story, obviously. However, he loves monsters and he likes that the girl "beats" the monster, so he's asked to read it quite a number of times since we got it from the library. And it's a good introduction to teaching about cleaning up waste properly, so it might be good to use for a lesson on that in the future.