Explores the rise of American power and influence from the end of continental expansion in the 1890s to the 'War on Terror' after September 11, 2001. Major crises in US foreign relations are considered in the light of changing historiography and international relations paradigms, notably those centred on: American 'exceptionalism'; Open Door imperialism; realist and national interest perspectives; isolationism and intervention; containment and bi-polar Cold War theories; decolonisation, post-colonialism and 'new imperialism'; globalisation and 'soft power'; Americanisation and anti-Americanism; debate over American empire and hegemony in the post-Cold War world; and the implications of the war on terror for the exercise of American power in the 21st century.