Accountability Shock presents the first systematic explanation of why some 'Third Wave' democracies developed peacefully while others became the world's most violent. The book demonstrates how robust transitional justice processes – combining truth commissions with prosecution of autocratic-era atrocities – prevent criminal violence in new democracies. By holding authoritarian specialists in violence accountable, new democracies can break state impunity, preventing them from becoming key actors in the production of large-scale criminal violence and reshaping the logic of state coercion in democracy. With in-depth analyses of six Latin American cases, the work illuminates why transitional justice is crucial for addressing state-criminal collusion in hybrid contexts. Forged out of a close collaboration between transitional justice scholars and practitioners, Accountability Shock strengthens existing connections while offering practical insights for countries still grappling with authoritarian legacies and violence.