Born by mistake, or connivance, to struggling parents in a small Lancashire cotton town in 1903, an uninspired Darlington inadvertently escaped the obscurity of farming life and rose instead, against all odds, to become within a few short years the world's greatest expert on chromosomes, and one of the most penetrating biological thinkers of the twentieth century. Harman follows Darlington's path from bleak prospects to world fame, showing how, within the most miniscule of worlds, he sought answers to the biggest questions—how species originate, how variation occurs, how Nature, both blind and foreboding, random and insightful, makes her way from deep past to unknown future. But Darlington did not stop there: Chromosomes held within their tiny confines untold, dark truths about man and his culture. This passionate conviction led the once famed Darlington down a path of rebuke, isolation, and finally obscurity. As unfolds Darlington's forgotten tale—the Nazi atrocities, the Cold War, the crackpot Lysenko, the molecular revolution, eugenics, Civil Rights, the welfare state, the changing views of man's place in nature, biological determinism—all were interconnected. Just as Darlington's work provoked him to ask questions about the link between biology and culture, his life raises fundamental questions about the link between science and society.