Providing a detailed survey of US diplomatic history in the twentieth century, this study combines narrative with analysis to explain how and why policy is made. The new edition has been updated to cover the period from 1900 to the present, including all eight years of the Reagan administration. Schulzinger critically examines the fundamental beliefs which have shaped US foreign policy since the turn of the century: a sense of superiority over other nations, a fear that various countries pose real and immediate dangers to US security, and an optimistic faith that US military strength, wealth, and political values can be applied to improve the lot of the world's peoples.