Concern over terrorism has become a part of life in the twentyrst century. Although terrorism is not new, the events of 9/11/2001 in the United States, the Madrid train bombings in 2004, the London transport bombings in 2005, continuing suicide attacks in Iraq and Israel/Palestine, and terrorist violence in many other places has focused attention on these types of events. Terrorism, of course, has occurred in many countries and in many contexts. It is not new phenomenon even though events such as these have made terrorism a more prominent concern in many countries. As a result, it is very important to have a better understanding of what terrorism is – why it occurs, who is responsible, what the terrorists hope to accomplish, and what the future holds for terrorism. These questions and others are basic to the topic of this book.