I'm almost 33 years old. I should be more mature than this.
So, more Oz. After L. Frank Baum died, his publishers wanted more Oz, because it still made them money, and they were big fans of money. Ruth Plumly Thompson was drafted (and approved by Baum's widow) and immediately set to work. Thompson was a notably more conservative writer, with far more European-centric ideas about fairy tales. This results in a lot of stories about princes and princesses and little forgotten monarchies spread throughout Oz. Also notable, as a result of her more conservative bent, is the rise in male protagonists, and the disappearance of characters of "lower class", like the Shaggy Man. These sound like negatives - and they are - but Thompson's books still hold together pretty well, especially as they go along. She ended up writing more of them than Baum himself, for what it's worth.
Of course, "Royal Book" highlights another unfortunate (but thankfully only occasional) trend in Thompson's work: casual racism. In this particular case, the Scarecrow rides his pole (heh) down to an underground kingdom, only to discover that he's actually a reincarnation of their lost king. This kingdom, and this is explicitly stated in the book, greatly resembles China, and I don't need to tell you the various ways in which the Chinese were described in 1921. It, uh... it hasn't aged particularly well.
Tune in Wednesday for lighter fare. It's a book about an elephant and a giant gnome, and it's not at all racist, that I can recall.