The Phantom Tollbooth is written by Norton Juster
Milo was a very unsatisfied child. He is the main character and is approximately 10 years old. He is unsatisfied because he is never content in what he is doing and never sees a purpose in doing things. He longs to be out of school when he is in, and he longs to be in when he's out. He often wonders what his purpose in life is. One day he finds a large package on his bedroom floor. He looks for an address to see who or where it's from, but finds nothing. After opening it, he finds a small purple tollbooth. He puts it together and drives through with a little car. As soon as he deposits the coin, he is instantly transported to a different place.
He brought a map that had a destination of Dictionopolis. The place he went to was the Kingdom of Wisdom. As he is driving, he losses concentration and becomes lost in the Doldrums. This is a place with no color where thinking is not allowed. He talks to the inhabitants of the Doldrums, called Lethagariams, for awhile and is soon rescued by a watchdog named Tock. Milo explains to Tock that he is looking for Dictionopolis and Tock agrees to assist him.