This collection brings together leading figures in the study of International Relations to explore praxis as a perspective on international politics and law. With its focus on competent judgements, the praxis approach holds the promise to overcome the divide between knowing and acting that marks positivist International Relations theory. Building on the transdisciplinary work of Friedrich Kratochwil – and with a concluding chapter from him – this book reveals the scope, limits and blind spots of praxis theorizing. For anyone involved in international politics, this is an important contribution to the reconciliation of theory and practice and an inspiration for future research. EPDFs of Chapters 1, 4, 9, 13, 15 and 16 are available Open Access under CC-BY-NC-ND licence.