The author argues that the conventional approach to ensuring safety - building in more warnings and safeguards - fails because it makes systems more complex and thus more likely to fail. For example, tests of a new safety system at Chernobyl nuclear power station helped produce the meltdown and subsequent fire. By recognizing two dimensions of risk - complex versus linear interactions, and tight versus loose coupling - this book provides a powerful framework for analyzing risks and the organizations that insist we run them.