Long before Google, Amazon, or Microsoft, computer technology shaped how people worked, how markets operated, and how businesses became big. After World War II, military officials and their partners in industry looked to the newly invented electronic computer as they sought to cut costs, speed up labor, manage supply chains, and—they hoped—bring stability to the postwar economy. Their efforts would shape early computer science and the first applications of computer technology in manufacturing and business, with profound consequences for workers and managers alike. By the 1960s, practices originally developed to improve industrial efficiency were being used by Wall Street, influencing how markets worked and even how traders thought. Digital technology became central to finance, tying together far-flung trading floors and automating decision making—with alarming consequences, including the 1987 Black Monday crash. Devin Kennedy offers a new history of the digital economy, showing how the computer emerged from—and transformed—capitalism in the United States. He traces how computer science and technology were made by industry, which molded computation to manage factories, financial markets, and entire firms. Drawing on the archives of businesses, computer researchers, regulators, and financial institutions, Coding Capitalism retells the story of the postwar economy and the computer, revealing how midcentury business laid the foundations of the digital world. Bridging business and economic history with the history of science and technology, this book uncovers the prehistory of big tech and demonstrates how capitalism has shaped computing since its invention.