Hurricane Katrina provided clear evidence that catastrophes are both qualitatively and quantitatively different from other disasters, illustrating that we are not prepared for events that simultaneously affect multiple states, large and diverse populations, multiple sectors of infrastructure, and the global economy. This book introduces the concept of catastrophes, provides descriptions of how they differ from disasters, and presents the science behind them. It examines how catastrophes can dramatically affect human populations and addresses new ways of planning for and preparing for these events and their aftermath.