The first act is an exhausting war adventure featuring a German U-boat at the outbreak of the Great War. Our hero and heroine, as well as a faithful dog, are torpedoed, rescued by a tug boat, sunk again by the same submarine, take over the German ship, lose command due to treachery, then resume control again only to be stranded off the rocky coast on an uncharted land after the ship is sabotaged. Geez! All this before we ever get to the Land that Time Forgot. In fact, I almost forgot about it myself.
Like "The Moon Maid," Burroughs followed this Radium-Age classic with two sequels that were eventually published as one volume. Together, they comprise the "Caspak Trilogy," which may not be as well read as his Martian stories, but are a fun ride for lovers of classic old school science fiction full of dinosaurs and civilizations of primitive humans.
There is a bit of a science mystery here, as it seems every gradient of human evolution exists on Caspak, with the more primitive tribes dwelling to the south, known as "the beginning," and growing more advanced further north. Each tribe has a religious understanding of what it means to be ready to travel north. I found this idea interesting and this is largely what motivated me to read more of the series.
Though I had a great time in this "Jurassic world," the actual narrative was rather devoid of sophistication. The surviving Germans aboard the U-boat can't be trusted, because, well... they're Germans in a Burroughs novel written during World War I. The heroine starts off as a spunky and capable character, only to be relegated to the damsel in distress wearing only a dainty slip of muslin and constantly being kidnapped by hairy apemen. The narrator is a ship builder, yet seems equally skilled at military command, hand-to-hand combat, hunting large and dangerous game, surviving in the wilderness, sewing an outfit out of leapord skins, and just generally being a superhero. How is he able to accomplish all of this? Burroughs offers no explanation other than to once say the character is from California, where all the residents are familiar with jujitsu. Oh really? I didn't know that, and I bet you Californians didn't know that either.
But all of that comes with the territory of early American escapist pulp entertainment. You can get some depth out of select Burroughs stories, but sometimes they don't age so well. What I have a harder time forgiving are the plot contrivances. The hero starts his adventure on a cruise ship that is sunk by the very submarine he designed and built, perfectly setting him up to be able to take over and captain the war engine himself. The only other survivor of the sinking is our heroine, who mentions that she was engaged to be married to a German, and lo and behold, the commander of the U-boat that sank her ship and almost killed her is her former fiance. I repeat--a U-boat sinks a passenger vessel, and the only survivors are the guy who designed the very same sub and the commander's girlfriend. What a stupid way to artificially move a plot along!
But again, you can't get too mad at this book. Either avoid it if this isn't your thing, or turn your brain off and enjoy.