Some 115 thousand years ago the world as we know it todayshifted into a much colder glacial mode which culminatedwith huge ice sheets reaching as far south as New York,Berlin and St. Petersburg. The numerical climate models,used to predict the next century climate, were as yet unableto explain what happened.The reader of the book gains a detailed picture of what isknown on the most important episodes of the past climatehistory, what to expect during the transition into aglacial climate mode, and which aspects and elements of theclimate system seem mostsusceptible to change. The climatemodelers will realize that the long term history of naturalclimate variations may hold important clues to the mechanismof climate changes which should be taken in account if thenear future CO2 rich climate have to be predicted with anydegree ofreliability.