From the world's most influential psychologist and bestselling author of Flourish, a landmark work spanning ancient Greece to the age of AI that identifies agencythe fusion of efficacy, optimism, and imaginationas the hidden engine of human progress, and shows how we can unleash it to build a better future.

What actually drives human progress? Ecologists point to geography and climate. Sociologists invoke wars and class. Economists follow the money. But none of these accounts explains why innovation and human thriving occurs in some eras and stalls in othersoften under identical material conditions. The missing variable, Seligman argues, is the psychological state known as: agency.

Agency is built from three interlocking capacities: efficacy, the confidence that you can accomplish a specific goal right now; optimism, the expectation that your efforts will pay off far into the future; and imagination, the breadth of goals you can envision. When all three align, civilizations leap forward. When they collapse, societies stagnateno matter how rich their resources or how brilliant their citizens.

Drawing on six decades of pioneering research and a sweeping reexamination of the last twenty-five hundred yearsfrom Periclean Athens and the Hebrew Torah to the Renaissance, the Enlightenment, and the Civil Rights MovementSeligman reveals how surges and declines in agency have quietly steered the course of history. With a clear-eyed look at an AI-transformed future, Agency makes the case that the power to create the next great era of human flourishing is already alive within each of us.