Upton Beall Sinclair Jr. was an American writer, muckraker, political activist and the 1934 Democratic Party nominee for governor of California. He wrote nearly 100 books and other works in several genres. Sinclair's work was well known and popular in the first half of the 20th century, and he won the Pulitzer Prize for Fiction in 1943.

The muckrakers were reform-minded journalists, writers, and photographers in the Progressive Era in the United States (1890s–1920s) who claimed to expose corruption and wrongdoing in established institutions, often through sensationalist publications. The modern term generally references investigative journalism or watchdog journalism; investigative journalists in the US are occasionally called "muckrakers" informally.