You should read this book if you are at all interested in ice ages, geology, history of science, climate change, or just a good story. It's a quick but thorough telling of the discovery of the ice ages and how their nature and origin have been slowly uncovered over the following 150 years (and still going!). No other book does so much in such a short space on the subject. One of the authors was personally involved in the story, so he has insider authority. Unfortunately, this probably accounts for the slower pace of the last few chapters, where events close to him are described in much greater detail. And even though the book is only 15 years old the last chapter (on a future ice age and the potential for global warming) seems outdated. Still, the book is well worth a quick read.

As a geologist, this book answered a lot of questions I've had concerning the cause(s) of the ice ages. I'd known about rumours about the configuration of the continents, Milankovitch's astronomical cycles, variation in sun output, changes in ocean currents, and so on, for some years, but I really needed a detailed analysis of the historical arguments, and the more recent evidence as to why these changes in the earth's climate occur. This book answers just about all I needed to know, as well as being a good study of historical science. It was some time before all the pieces began to fit, and there are still some unexplained aspects, such as why the 100,000 glacial cycle is stronger than the 20,000 and 40,000 year cycles. Also, early arguments revolving around the Biblical flood are enlightening.

This book details all the theories, and the history behind their development. From deep sea radiolarians, to terraced reefs in the equatorial regions, to vegetation studies in Europe, to the level of snow on Ethiopia's mountains, to axis and ellitpical variations in the earth's orbit, to the gravitational effect of the pull on the earth from other planets, to oxygen isotope studies, to graphs of variation in thermal energy, temperature and sea level at different lattitudes-both expected from Milankovitch cycles-and actual from deep sea analysis, this book pretty much covers all you need to know. The only drawback is it has missed a few recent ideas in the 1980s to 1990s, but the story was pretty much over by then. Pretty conclusive evidence is detailed on how regular and episodic variations in the earth's orbit around the sun trigger periodically cooler climates than at present. These have been particularly strong in the last 1.5 million years or so, which is thought to do with the configuration of recent continental geography. In the last 7,000 years the tmeperature has dropped around 2 degrees, and will continue to drop over the next several thousand years at least, albeit very slowly, if it wasn't of course for the already verified greenhouse warming. Unfortunately, being published in the late 1970s, the book has not captured much of the recent data and debate concerning the greenhouse effect, but is nevertheless an intriguing and enlightening expose of earth climate variations.

The other thing which struck me just a little, was the fact that the major ice age periods in the earth's past have been at or around 3 interesting changes or developments in evolutionary history-the Permo-Carboniferous (ie Permian-Triassic extinction), Pre-Cambrian (multicelled organisms), and Quaternary-Recent (hominids). Certianly the hominid succession has been mostly within major changes in the earths climate, including significantly colder periods, and vast ice sheets across northern lattitudes. Maybe coincidental, but something to think about.

I found this a well written account of the subject. The authors include an extensive history of the intellectual development of the concept as well as scientific documentation of the cyclical nature of ice ages. This would be a good book to read along with The Ice Finders, which is a somewhat more intimate account of the early research on ice ages.