This book, like many others, owes its existence to the terrorist attacks of September 11, 2001. Nonetheless, the problems that it deals with existed long before these attacks. Many of these problems have been preoccupations of mine for a long time. Although I have never fought in a war or lived in a war zone, war, violence, and threats of destruction have loomed large throughout my life.

While many questions can and should be asked about war and political violence, my main focus will be on moral questions. Because of the September 11 attacks and the subsequent “war on terrorism,” I begin with moral questions about terrorism. Much of the book, however, deals with more general moral questions about war and violence. The reason for this is that we cannot have morally credible views about terrorism if we focus on terrorism alone and neglect broader issues about the ethics of war.

My aim in this book is to answer five questions:

1. 1. What is terrorism?

2. 2. If terrorism is especially wrong, what features of terrorism make it especially wrong?

3. 3. If terrorism is especially wrong, why do moral condemnations of terrorism often lack credibility? Why do they evoke cynical responses rather than affirmations of respect for human life?

4. 4. What conditions must be met in order for condemnations of terrorism to be morally credible?

5. 5. Is terrorism always wrong, or can it sometimes be morally justified?