Standard Oil & John D. Rockefeller
John D. Rockefeller built Standard Oil starting in 1870, at the dawn of the petroleum age, and assembled the first great industrial fortune in American history.
Organizing an industry
Rather than strike it rich on a single well, Rockefeller dominated refining and distribution. Through efficiency, secret railroad rebates, and the steady absorption of rivals, Standard Oil came to control the vast majority of American oil — a near-monopoly organized as a pioneering 'trust.' That power provoked a backlash, including Ida Tarbell's landmark exposé, and in 1911 the Supreme Court ordered the company broken into dozens of pieces, several of which became today's oil giants.
Rockefeller became likely the richest American of his era, then a major philanthropist. The story is a foundational study in scale, monopoly, and the antitrust response it triggered.
Takeaway: Huge fortunes are often built not by inventing a product, but by organizing an entire industry more efficiently than anyone else.