There are signs that the ice of the ancient Great Ice Age --still extant in Arctic and Antarctic regions -- is spreading once again. Scientists are studying and measuring. The author of this book was one of the aviators in Operation Deep Freeze in the Antarctic, and has flown over both poles. In this book he examines what is known of the ice ages of the past, and uses his knowledge of glaciers, of icebergs, of the ice caps of arctic regions to project his imagination into a possible future. Here is a different sort of book on natural science, and the author writes with the sweep appropriate to the drama of his material.