Upton Beall Sinclair, Jr.

After an early career writing pulp fiction and several failed idealistic novels, Upton Sinclair became a socialist and published The Jungle—one of the most influential novels of its day—in 1906, the year this photograph was taken. Intending to expose corruption and wretched conditions for workers, Sinclair had spent seven weeks living in Chicago's meatpacking district. But The Jungle also revealed the appalling sanitary conditions of the industry. "I aimed at the public's heart," he later recalled, "and by accident I hit it in the stomach." The book, an international sensation, prompted Theodore Roosevelt to invite Sinclair to the White House; the president signed the Pure Food and Drug Act and the Meat Inspection Act shortly afterward. Motivated by his concern for social justice, Sinclair continued to write historical novels and exposés, becoming one of the Progressive Era's best-known muckrakers.

This photograph was taken at Sinclair's small farm near Princeton, New Jersey, in 1906, the year he ran for Congress as a socialist.