American novelist Upton Sinclair is most famous for his 1906 novel The Jungle and the reforms to which it gave rise. Sinclair was a muckraker—so dubbed by President Theodore Roosevelt, who regarded them as a nuisance—one of a group of journalists who were relentless in their exposure of corruption in American business and government.

Sinclair intended his book, set in the Chicago meat-packing industry, to arouse support for the plight of immigrant laborers. He exposed the political machinations of the Democratic and Republican parties and put forward the Socialist Party as the only trustworthy organization. Instead, The Jungle triggered outrage at the malfeasance of the meat packers, who had little care that much of their processed meat was adulterated with dirt, dung, poisoned rats, and the odd human body part. Roosevelt apparently read the book and dispatched investigators who confirmed the veracity of...