My almost two year old daughter is much more observant than my wife or I. When she sees this book, she says "wolf, scared." She then reflects on her response and says "crying." If you try to get near her with the puppet wolf mouth she runs away.
Wondering what was up, I took a closer look. On one page, it's time for Mr. Wolf to read. If you look carefully, he's reading a Cook Book with a picture of children in a stew pot on the cover. The children wolves are sitting at a little table with tea-set plates and silverware, with a doll on the main platter. When you get to the final page, it's 6:00, time for dinner. It seemed to my wife like a meaningless let-down, until we noticed that the whole wolf family is looking out at the reader/child, implying that YOU are dinner.
I should mention that the book is recommended for 3+, and my daughter is not yet 2. Maybe a 4 year old would like it.
If you're looking for a nice puppet book for kids, look elsewhere. If you WANT a really creepy kids book, this is one of the best. The "I'm going to eat you" references are a little subtle, and so all the more creepy.