This edited volume examines concepts of sincerity in politics and international relations in order to discuss what we should expect of politicians, within what parameters they should work, and how their decisions and actions could be made consistent with morality. The volume features an international cast of authors who specialize in the topic of sincerity in politics and international relations. Looking at how sincerity bears on political actions, practices, and institutions at national and international level, the introduction serves to place the chapters in the context of ongoing contemporary debates on sincerity in politics and international theory. Each chapter focuses on a contemporary issue in politics and international relations, including corruption, public hypocrisy, cynicism, trust, security, policy formulation and decision-making, political apology, public reason, political dissimulation, denial and self-deception, and will argue against the background of a Kantian view of sincerity as unconditional. Offering a significant comprehensive outlook on the practical limits of sincerity in political affairs, this work will be of great interest to both students and scholars.