Margaret Sanger's The Pivot of Civilization is a fierce, wide-ranging argument that birth control is not a private preference but a decisive issue for modern society. In H.G. Wells's introduction, the book is framed as a clash between two civilizations: one built on obedience, inherited authority, and repression, the other on inquiry, science, and human self-direction. Sanger writes from lived experience, not academic distance, drawing on labor struggles, political activism, and encounters with women workers to show that poverty, exhausted mothers, malnourished children, and social injustice are bound to unchecked reproduction as much as to wages or law. Moving from industrialization to war, she argues that modern machinery, overcrowded cities, class division, and global conflict have exposed the failure of old assumptions. Labor movements, churches, the press, philanthropy, and even Marxist orthodoxy all come under fire for ignoring sex and reproduction. Birth control, she insists, means intelligent guidance of reproductive power—and a path toward freer families, social improvement, and a more humane civilization. This edition has been fully restored with modern typesetting, custom cover design.