A connected world is vulnerable to cascades and contagions. I will introduce concepts of complex systems science that characterize dependencies and collective behaviors. I will show how these concepts and the mathematical tools underlying them can help us understand and even anticipate the global crises we are facing, including the global financial crisis, the global food crisis, riots and revolutions and the Ebola epidemic. These crises often arise from the unanticipated effects of policy decisions and can be effectively addressed only by understanding those effects. Professor Yaneer Bar-Yam is the founder and president of the New England Complex Systems Institute, an independent academic research group applying complex systems analysis to science and social concerns, and Research Scientist at MIT. His recent work explores the origins and impacts of market crashes, ethnic violence, social unrest, pandemics, social networks, and the basis of creativity, panics, evolution and altruism. His work on the causes of the global food crisis was cited as among the top 10 scientific discoveries of 2011 by Wired magazine. Professor Bar-Yam has advised governments, NGOs, and corporations on using principles and insights from complex systems science to solve seemingly intractable problems, including: the Centers for Disease Control and Prevention, the Securities and Exchange Commission (SEC), the United Nations, the World Bank, groups across the branches of the United States military and intelligence community (e.g. the CIA, NSA, and TSA), and corporations such as Boeing, Lockheed-Martin, Raytheon, and SAIC. He advised Congressman Barney Frank in his role as Chairman of the Financial Services Committee, and consulted with Congressman Michael Capuano on the financial crisis. He has advised the Chairman's Action Group about the role of high food prices in causing widespread social unrest (the "new normal"). Bar-Yam has been a Visiting Scholar at the Federal Reserve Bank of Boston. Professor Bar-Yam received his SB and PhD in physics from MIT in 1978 and 1984 respectively.