This book investigates the persistent presence and defining characteristics of extremist movements and individuals throughout the course of American history. Archer examines a wide spectrum of figures and groups, from the revolutionary fervor of the colonists to the violent acts of assassins in the latter half of the 20th century, to understand the underlying motivations and societal impacts of extremism.

The book is presented as a historical survey of extremism in America. Its scope suggests a broad overview of various movements and individuals who have challenged established norms or engaged in radical actions. The author's approach likely focuses on tracing patterns and characteristics of these groups across different historical periods, offering a chronological perspective on radicalism's role in American society.