In this volume a group of distinguished moral and social thinkers address the urgent problem of terrorism. The essays define terrorism, discuss whether the assessment of terrorist violence should be based on its consequences (beneficial or otherwise), and explore what means may be used to combat those who use violence without justification. Among other questions raised by the volume are: What does it mean for a people to be innocent of the acts of their government? May there not be some justification in terrorists targeting certain victims but not others? May terrorist acts be attributed to groups or to states? The collection will be of particular interest to moral and political philosophers, political scientists, legal theorists, and students of international studies and conflict resolution.