This is a favorite of mine. I have mentioned before that I wasn't a reader as a child. I came across this excellent book as a homeschool mom when I saw it on a library display table.
If you love words and their creative uses you will love this book. Read it.
Here is a video about the book and the love of it:
The Phantom Tollbooth Turns 50
Juster explains that this was his first attempt at writing for children and that the thinking at the time was that fantasy was bad for children. I'm glad he ignored that and wrote the book!
I love this book! I read this to our children in 2003. I read it again, to our middle child this year, in February.