This book explores how, underneath the mask of imperial power, material facts such as rivers and winds, tools and technologies, the impetus and drag of older social and cultural structures, shape global history. Empires make world history, but they do not make it exactly as they choose. The facts of geography - mountains and marshes, rivers, winds and ocean currents - and of human technology, social organisation and culture determine how social power is constituted in space. Most historical writing has found its impetus in forms of patriotism, and has obscured the complexity of interests that underlie empires, and their modern heirs, nations. Masks of Empire consists of provocations which seek to push historians to consider the very long term history of cultures of domination, the role of rivers, winds and currents, the unity of European imperialisms, the 'New Imperialism' as part of the global history of Bureaucracy, the British and American empires as effects of global history rather than its drivers, the complex temporalities of imperial expansion and retreat, and Twenty-first century imperialism.