As control engineers and scientists, we have greatly altered the way people and nations live and interact with one another. We have helped to create a world in which people live longer, enjoy better health, are better educated, and can travel and communicate over greater distances. But the systems that provide these better lives are fragile systems subject to unpredictable failures and possible destruction. We have also helped to create a world in which international relations are such that the very civilizations we have helped to build over centuries can be destroyed in a matter of hours.