Pretend play is important work-- for real!
When children play make-believe, they are actually building their pre-reading skills. The ability to symbolize, to know that the word "princess" on a page connotes a certain image of royal girly fabulousness, is an important concept they will need to understand before they can learn to read. When they are three and pretend to be a different creature every hour, they are studying this very thing. When they take a stick and turn it into a magic fairy wand, or a warrior's sword, the power of symbolic thought is hard at work in your preschooler. So you can feel like you're preparing your children well when you bring home these books for your superheroes and princesses at home. Just be prepared-- they may ask you to be the dragon once in a while.