Presenting an analysis of modern-day extremism, this book explores how any group of people or participants in a movement--political, ideological, racial, ethnonational, religious, or issue-driven--can adopt extremist mindsets if they believe their existence or interests are threatened. Looking beyond "fringe" resistance groups already labeled as terrorists or subversives, the author examines conventional organizations--political parties, religious groups, corporations, interest groups, nation-states, police, and the military--that deploy extremist strategies to further their agendas. Dynamics of mutual causation process between dominant and resistant extremist groups are explored, including how resistant extremisms surface in response to oppressive and abusive measures advanced by the dominant groups to further their interests and maintain supremacy through systemic injustices, as happens in slavery, caste systems, patriarchy, colonialism, autocracy, exploitive capitalism, and discrimination against minorities.