The international drug control regime, built on three conventions (1961, 1971, and 1988), prohibits non-medical drug production and use while ensuring access for medical purposes. Despite nearly universal ratification and efforts focused on demand and supply reduction, the illegal drug market has expanded, with drug use increasing by 20% and problematic use by 45% in just a decade. Challenges such as synthetic drug crises, the legalization of non-medical cannabis in some regions, and new trafficking methods like cryptomarkets have highlighted tensions within the regime and its limits in meeting key objectives. This book examines the framework's legal foundations, implementation, and historical context, alongside emerging tensions and their impact on global norms related to health, development, and human rights. It explores whether the regime remains fit for purpose or requires reform, assessing existing pathways for change and the implications of maintaining the status quo or of reforming. The book provides valuable insights for policymakers, academics, and communities grappling with the modernization of drug control laws in the face of evolving challenges.