Some literary critics rank the first novella "The Land That Time Forgot" as Burroughs's best work. It has at its center an ingenious concept — that of a world in which the outside world's evolutionary history is lived through from beginning to end by individual people. Burroughs takes care to develop this idea fully, making it a satisfying mystery to be uncovered by the unwilling explorers from the U-boat.

Other elements are standard fare for one of Burroughs's adventures. Coincidences appear whenever they will help the plot move forward, and Burroughs seldom offers explanations for them. A love story helps keep the novella well focused, and provides much of its sense of direction. Tyler is a typical Burroughs hero; he is somewhat bland but gifted with leadership qualities that make those around him willing to follow wherever he leads. He is a bit prudish, which seems to add...