I feel like every week, Mr. S. is into something new. For a while it was cars, then it was the solar system, sports, and animals. When he goes on one of these "jags" we have to read what feels like a million books and web pages on the subject. The thing about them is though, he will repeat himself. So while he's not interested in the moon or Mars at the moment, I know that at any time, he could suddenly be begging me to go to the library so we can take out some books.
The next time he wants to learn about dinosaurs, I have the perfect resource -- The Dinosaur ABC by About.com's Guide to Dinosaurs, Bob Strauss. Filled with 26 informative entries, as well as illustrations, both kids and grown-ups alike will get a kick out of learning about all the different prehistoric creatures that roamed the earth.
What does your preschooler like to learn about?