There is a lack of empirical data for testing various theories of radicalization, and little attention has been given to varieties of domestic terrorism related to such issues as environmental protection, animal rights, and radical right-wing and left-wing ideologies. It is important to study the radicalization process, since it typically involves an evolution of ideological beliefs, attitudes, and behaviors in the face of challenges to those beliefs. An examination of this process involves studying the life histories of those who engage in violent behaviors linked to strong beliefs and ideologies. The research proposed by Ackerman will involve the collection of cross-sectional data on 1,800 individuals from across the ideological spectrum. The only criteria are that they must have been radicalized in the United States and have been indicted for a crime or been killed in the commission of a crime in the United States. A focus will be on differences between those who engage in violent acts and those who engage in nonviolent acts in promoting their ideology. Attention will be given to how behaviors differ across ideologies, as well as indicators of the increased risk for violent behavior.