The phantom tollbooth:

Fantasy Characters:15 male and female Simple set. Here are Milo's adventures in the Land of Wisdom where he's forced to think about many new things. Milo learns of the argument between King Azaz and his brother, the Mathemagician whose disagreement over words and numbers has led to the banishment of Princesses Sweet Rhyme and Pure Reason. Milo is dispatched to rescue the Princesses from the Land of Ignorance. The knowledge and skills Milo picks up on his journey help him to save the Princesses. When he must return home, Milo's sorry to leave his friends-- but enriched by his experience, he realizes his attitude towards learning will never be the same.