The private pension is a curiosity in the modern economic environment. Why do profit-seeking companies pay retirement benefits to those no longer on the job? In this new institutional history, Steven Sass explores the rise and growth of the financial support system that today commands trillions of dollars of investment capital and supports hundreds of thousands of older Americans.

Before 1900 America's elderly derived their livelihood from simple sources. They worked if they could, relied on their children, and took charity if necessary. By the dawn of the twentieth century, however,...