Gregory Zuckerman's definitive account of Jim Simons and his secretive quantitative hedge fund, Renaissance Technologies, tells the extraordinary story of how a mathematician with no formal finance training built the most successful investment firm in history. Simons, a former codebreaker and award-winning mathematician, assembled a team of scientists, statisticians, and computer scientists who approached markets as a data problem rather than an economic or fundamental analysis problem. Their flagship Medallion Fund, closed to outside investors since 1993, generated average annual returns of approximately 66% before fees over more than three decades — a record that dwarfs every other investment manager, including Buffett, Soros, and Lynch. Zuckerman traces Simons's intellectual journey from academic mathematics through defense research and into finance, documenting the specific breakthroughs — the shift from fundamental to purely statistical models, the discovery of mean reversion signals, and the development of market-neutral strategies — that gave Renaissance its edge. The book also explores Simons's personal life, his philanthropic activities, and the controversial political role played by former Renaissance executive Robert Mercer. A compulsively readable account of how quantitative finance came to dominate Wall Street.