No one can forget the horrific images of the destructive power of the tsunami that engulfed Southeast Asia on Boxing Day in 2004, or the chaos wrought by Hurricane Katrina. Could these 'megadisasters' have been predicted? This book is about the science and mathematics that underlies efforts to understand and predict megadisasters. There are similarities in the variety of cataclysms that we are prone to, whether hurricanes, tsunamis, sudden changes of climate, or stock market crashes. These are all events that are associated with complex systems, with many variables, and their science and mathematics is that of 'chaotic systems'. Their behaviour is very difficult to predict. Other kinds of megadisasters are the risk of a massive asteroid impact, and the development of pandemics. Understanding and predicting these phenomena involve developing complex mathematical models, and we have a long way to go. In this book, Diacu describes the struggles of mathematicians and scientists over the centuries to get to grips with the nature of volcanoes, hurricanes, and other complex phenomena and prevent future tragedies. But he also includes human stories that remind us of their terrifying power and the experience of being caught up in them.