What caused the great ice ages long before man inhabited the earth, and are we in danger of a new one? The pre-eminent science writer of our time takes the reader on an immense polar journey, through past and present, in one of his most timely and important books.

The polar regions directly affect us and our lives in many profound ways. And much new knowledge has recently come to light about the top and bottom of the world, including answers to some of the most baffling mysteries about the ice ages, all of which appear in the pages of this wide-ranging book. Why did the giant ice sheets cover large parts of the Northern Hemisphere and not the Southern? Why were the ice ages of the last million years preceded by hundreds of millions of years without an ice age? And what is the current thinking about a new ice age immediately ahead?

The ever-changing global relationships of sun, atmosphere, and ocean; the polar implications of the new knowledge of drifting continents; the present and prehistoric flora and fauna; electromagnetic fields and world-wide weather; the surprising differences between the Arctic and Antarctic; the voyages of the earlier geographical explorers as well as later scientific expeditions—all these freshly re-examined subjects are given extensive attention in one of Asimov’s most engrossing narratives to date.

This volume is among the rarest of Asimovian birds—a book about geography.

As one would expect, it’s thorough and exhaustive. Asimov details the astronomic facts that govern the climate of the arctic and antarctic regions, the history of their exploration, their flora and fauna, and so on, all in a clear and simple fashion. (Particularly worthwhile is his excellent explanation of why the polar regions are so cold even when the sun is shining all day.)

To add to the book’s rarity among Asimov’s opera, it’s beautifully illustrated with line drawings; the drawings are particularly excellent of the polar region’s animal residents.

This is a marvelous book, among my very favorites of Asimov’s nonfiction. It’s definitely worthwhile for anybody who wants a basic introduction to the top and bottom of our planet.