Synopsis: Adam knew that the creatures who surrounded him had vanished from the earth five million years ago. Their beautiful art, their terrible weaponry, their religion, customs and language, even the animals they hunted and the alien dark tribe against whom they waged eternal war, all belonged to a time before the great glaciers had retreated and man had assumed control of the globe. But Adam was in no position to deny their reality. For now he and his companion, the renowned Professor Karl Belgrade, were being led to their ruler-the young and beautiful Queen who would decide whether the intruders would live or die. The last ravings of a man dying from a mysterious fever and the haunting hypothesis of a brilliant and obsessed scientist were all that the two explorers had to go on as their tiny plane winged high over the menacing Antarctic ice. They find a secret valley that only one human being had ever visited and lived to tell about it, a lost world ruled by creatures from the darkest depths of time, who even now might be playing out a gigantic contest between good and evil to its strange and terrible conclusion. (adapted from the texts published with the 1972 edition)