This book analyses the domestic application of international law, with a particular focus on the concept of direct applicability. It critically examines the relevant doctrine and practice and proposes a new analytical framework. It argues that international law is presumed to be directly applicable, that the criteria for direct applicability are grounds to exclude rather than establish direct applicability, and that the positive intent of the parties should not be a criterion. It contends that direct applicability is a question of domestic law and that domestic legal force is a prerequisite for direct applicability. It also advocates a relative approach.