Juster's famous novel is described in the introduction as being about the value of education - I certainly agree with that but I think it is also something a little more specific and personal to Juster; how to view the world. For example the chapters on not looking at one's environment and noise pollution are not really about what one learns in school.
I was recommended the book after I mentioned why I liked Lemony Snicket's A Series of Unfortunate Events - wit, puns, word-play. There is much of that to be found here but not a hint of the moral ambiguity that appears in the later Snicket books.
A fun book, though largely preaching to the converted in my case.