Volume 3 describes the history of the foreign relations of the United States during 1913–1945, the period of two world wars as well as of momentous changes that brought to an end the period of European domination. The United States emerged as the key global power, actively participating in wars but also promoting trade and investment activities throughout the world, as well as ‘Americanising’ other countries’ ways of life and habits of thought. The book is thus not a usual survey of foreign policy decisions but tells a story about America’s growing involvement in all parts of the world and in all aspects of twentieth-century life.