I read TARZAN THE UNTAMED when I was in the sixth grade, as I mentioned a couple of weeks ago, and I soon followed it up with the sequel, TARZAN THE TERRIBLE, which I'd never reread until now. This one starts out with Tarzan continuing the search for Jane, who's been kidnapped by German soldiers during World War I. He soon discovers that she's escaped from her captors and set off on her own, and in trailing her Tarzan finds himself in another of Edgar Rice Burroughs' vividly created lost civilizations, this one the land of Pal-ul-don, enclosed by an almost impenetrable swamp. This isolation has allowed prehistoric species to survive, such as the triceratops, known to the inhabitants of Pal-ul-don as a gryf. Humanity has evolved differently in Pal-ul-don, too, and the people there have tails, among other oddities.
It's strange, looking back on that time more than fifty years ago, and remembering that when I first read them, TARZAN THE UNTAMED was my favorite of this linked pair, although I liked TARZAN THE TERRIBLE just fine. My opinion has turned around with this recent rereading. I think TARZAN THE TERRIBLE is a much better book. Still, I liked them both and am happy to have revisited them five decades later. (The scan at the top is from the Ballantine edition, with cover artwork by Richard Powers. That's the edition I read there at the Rock School when I probably should have been doing actual schoolwork. But hey, in reality I was studying for my career, I just didn't know it at the time.)