This collection is an introduction to both American history and to the Core Documents project of Teaching American History. As an introduction to American history, it focuses on several key themes and ideas that have shaped our history, including equality and liberty, race and civil rights, religion and politics, America’s uniqueness and place in the world, the relationship between the states and the federal government, and the federal government and the daily lives of Americans. It presents these themes and ideas as Americans thought about them when the United States was an agrarian republic, as it developed into an industrialized nation-state, and as it most recently struggled with the consequences of its success in creating a globalized economy and liberal international order that, to a remarkable degree, reflects the guiding principles of its own continental expansion. Those guiding principles were, in turn, formed from the central principle of all American history and politics, human equality, as expressed in the Declaration of Independence.