The African Union marks a new era in institution-building in postcolonial Africa. It is conceived as an aspect of Africa's response to the challenges of globalization and regional integration. It is also part of the historic quest for deeper African unity. This discussion focuses on the political and contextual dynamics behind this development, and assesses its significance for the project of African integration. While offering no extensive examination of all the core provisions of the Constitutive Act, particular attention has been paid to some key principles. It is argued that the African Union represents a significant departure from the political, legal, and institutional framework of the OAU, and is predicated on a range of principles that reflect new thinking and approaches among the African states.