Around 4000 years ago the advanced urban civilizations in Egypt, Mesopotamia and India suddenly collapsed. What happened? Did a prolonged drought cause the breakdown of social order? Recent discoveries from all over the world strongly support the suspected link of the collapse with climate. The volume presents the findings of more than 40 researchers and provides a review on the relevant information. It appears that a major shift of the precipitation pattern affected many parts of the world at approximately the same time, with disastrous effects on the nomadic populations of Asia, Africa and Eastern Europe. Can a similar climate shift with a serious adverse impact on society happen again? In a world facing global warming, there could be many lessons to be learned from the experiences of ancient societies.