The article discusses how a book called "Risk, Uncertainty, and Profit" influenced economic theory in the 20th century. It shows that before World War II, early neoclassical economics shared common ideas with the book. After the war, two different approaches to economic thought emerged. One approach, called microeconomics, focuses on maximizing utility under specific conditions. The other approach, known as price theory, sees prices as guides for decision-making in different situations. These approaches shaped ideas about uncertainty, profit, and entrepreneurship, as well as how economies are organized and progress socially.