The newest volume in Taylor’s U.S. history series, after American Revolutions, covers the post-revolutionary period through the Compromise of 1850; it counters widespread beliefs about U.S. geographic expansion. Taylor argues that the colonial push westward was driven by perceived threats to the precarious union—from distant and neighboring governments; Indigenous peoples displaced and attacked by the colonies; free and enslaved Black people; and short-lived republics developed by restive colonists. Taylor underscores the complexity of persistent U.S. instability: fear of these varied groups drove Anglo continental invasion, and each territorial advance increased regional tensions and mistrust, resulting in continual risks of disunion. Racism was an underlying cause of U.S. expansion and insecurity: see, for example, self-interested white Americans who, believing that people of color shouldn’t have their own land, brutally wrested arable territory from Indigenous peoples and non-white immigrants; Southern slaveholders who perpetuated slave labor and feared rebellions by enslaved people; low-income white Southerners’ whose status depended on their ranking above enslaved people; and the North’s bowing to threats of Southern secession because the economy relied on cheap cotton and because, despite Northerners’ theoretical abolitionism, they did not want to have Black neighbors. VERDICT This insightful and engaging survey is essential reading for scholars as well as casual readers of history.