Who is the collaborator, or in whose eyes? What is the motivation to collaborate? For material gain, for ideology, for duty? When is collaboration betraying a hated enemy, and when is it something else: personal revenge or an instrumental, rational, or even coerced response to a situation, for example? Why do collaborators meet such harsh punishment and stigma when they are revealed as such? Can they ever atone or find redemption? Beyond the perception of the stakeholders involved, how harmful is collaboration? Does it exacerbate or abate violence? Is it always evil or can it sometimes be seen as mitigating wrongs? The chapters in this book explore these thorny questions through a set of case studies, disciplinary approaches, and temporal and regional contexts. They show the range of the types of collaboration, and the ubiquity of collaboration across time, countries, political systems, and political and cultural conflicts.