Part of the Darwin College Lecture Series 2010. Social scientists tell us we now live that we live in a world risk society. But what does this really mean and what, if anything, do environmental risks, health risks, and natural disasters have in common with those posed by terrorism? When we move from the natural world to human threats are we still dealing with hard science or are we in the realm of speculation? Are the presumptions behind risk based counter-terrorism policies and the profiling of terrorist suspects safe? Terrorist acts are exceptionally rare but they pose the risk of catastrophic harm. No surprise then that we consent to intrusive measures that erode civil liberties in the name of avoiding such harms. The conceit of balancing liberty and security assumes that by degrading liberty we can reduce risk. In place of balancing might we do better to ask what really is at risk in the war on terror? We think of the risks posed by terrorism primarily in terms of subjective insecurity and threat to life and property. But countering terrorism carries its own risks risks to social, political, and economic life and risks to rights (rights to freedom of speech, to privacy, and to freedom of the person). Add to this the risk of marginalising and alienating those we target and we are in danger of allowing responses to terrorism to generate a whole slew of new risks. So my question is what risks are at stake and how we might live with risk without living in terror.