The first of his Caspak trilogy. His working title for the story was "The Lost U-Boat." The sequence was first published in Blue Book Magazine as a three-part serial in the issues for September, October and November 1918. When adventurer Bowen Tyler was taken captive aboard an enemy submarine, he never dreamed that his voyage would end in the land that time forgot. It is a land called Caspak, a land of myth and fable: located somewhere on a mountainous island in the South Pacific, populated with winged, humanlike creatures, dinosaurs, ferocious beasts of prey, Neanderthals, "wild ape-men," and monstrous reptiles who all terrorize one another -- and Bowen Tyler, and the submarine's mixed crew of World War I-era adventurers. Stranded on the beach, they fight their way across the island, through dinosaurs and Bronze Age warriors, saber-toothed tigers and cunning beast-men. They dine on Plesiosaurus steaks and face incredible dangers, meet and fall in love with a jungle princess -- and unravel the incredible secret of Caspak. . . .