This chapter surveys how international legal scholars have catalogued and sought to explain the legal impact of the UN even though its political and judicial organs have not been delegated the power to make law. It explains how the UN attempts to adhere to, but also challenges, the traditional sources of international law—treaties, custom, and general principles—contained in the Statute of the International Court of Justice. It enumerates how the turn to UN system organizations—amidst newly empowered non-state actors, increasing resort to ‘soft’ or ‘informal’ norms, and recourse to institutionalized processes—have led to distinct legal frameworks such as process or deliberative theories, interdisciplinary ‘law and’ approaches, feminist and ‘Third World’ critiques, and scholarly work that renews attention to or revises legal positivism.