I put the kid to bed this evening and found that he was sleeping with a copy of The Magic of Oz, my favorite of the Oz books because it's the one with both the glass cat and the magic island that makes your feet grow roots. I read all fourteen aloud to him years ago, and now he reads them on his own. They were some of my favorite books, growing up, and were my dad's, too. However, aside from the three of us, I don't know anyone else who's read them. That's nuts! Because they're great: each book is a long, crazy, imaginative adventure that manages to avoid all of the cliches that bog down so much of children's literature. There are girl heroes and boy heroes, and boys that turn into girls, and of course all kinds of strange and magical creatures. (Wish I could be more specific, but our copies of the books are all in my son's now darkened bedroom.) What I like best about them is the way Baum seems more interested in delighting and surprising his readers than in scaring them or teaching them a lesson. They are food for the imagination, and not much else.
Anyway, I just wanted to mention them as part of my appreciating the underappreciated thing. Though they're a hundred years old, the books aren't especially dated and are even easier to read than Harry Potter, so I don't know why they're not more popular.