How can we determine an acceptable level of risk? Should these decisions be made by experts, or by the people they affect? How should safety and security be balanced against other goods, such as liberty? This is the first collection to examine the philosophical dimensions of these pressing practical problems. Leading scholars exploring the full range of philosophical implications of risk, including risk and ethics; risk and rationality; risk and scientific expertise; risk and lay knowledge; the objectivity of risk assessment; risk and the precautionary principle; and risk and terror. With contributions from Carl F. Cranor, Sven Ove Hansson, Martin Kusch, Tim Lewens, D.H. Mellor, Adam Morton, Stephen Perry, Martin Peterson, Alan Ryan, Per Sandin, Cass R. Sunstein and Jonathan Wolff; this collection is essential reading, not only for philosophers and researchers in legal, economic and environmental studies, but for those seeking to gain a better understanding of the decisions we must make as concerned citizens.