After 50 years, Juster is still flummoxed as to why his book turned out to be such a success. Children surprise you, he says. When they read a book, they may experience it or appreciate it in a way that’s totally different than what the author intended. But that’s OK, he says. Sometimes writers feel like their job is to communicate a specific idea or a finite point of view. “I think the idea rather is to open up a piece of the world to a more creative encounter,” Juster says.

[emphasis mine]

I just read Phantom Tollbooth in May–loved the wordplay. Really a LOT of fun to read as an adult. (If I read it as a child (?) I had forgotten it.)