Global terrorism has become a frightening reality. From New York City and Washington, D.C., to Bali, Moscow, and Madrid, ordinary citizens throughout the civilized world live with increasing fear of a deadly attack from unknown individuals, for reasons many of us cannot fathom. National and international security forces are on constant alert, desperate to prevent the next catastrophe, and yet many observers agree that our military and intelligence services are spread too thin and face insurmountable hurdles in the global war on terrorism. The situation calls for greater engagement with the public, as the necessary eyes and ears of the global anti-terrorism coalition. However, to be effective the public must be equipped with the knowledge of how, why, and where an individual becomes a terrorist. This is the primary goal of this set, which seeks to answer one central question: What do we currently know about the transformation through which an individual becomes a terrorist?