Portrait of Ida Tarbell created between 1910 and 1930. Wikipedia

The November 1903 cover of McClure's Magazine listing articles by male muckrakers. A few years later, future Pulitzer-winning author Willa Cather would be managing editor of McClure’s; Cather worked in journalism for years prior to writing her famous novels. Library of Congress LC-USZ62-75558

The influence of investigative journalism upon social, economic, and political reform increased with the Progressive Era of the late 19th and early 20th centuries. Ida M. Tarbell exemplified this trend, beginning her career with McClure's Magazine in 1894. She led the “muckraker” journalism movement, which sought to expose corruption and injustice in American political and economic structures. In 1902, Tarbell published a groundbreaking 1902 series of articles that together were titled “History of the Standard Oil Company.” Despite the arcane title, Tarbell's work attracted major national attention for its indictment of the Rockefeller corporation's monopolization of the oil industry and its continued violation of new anti-trust laws. She joined several other muckraking journalists in launching The American Magazine in 1906. She wrote and co-edited that journal until 1915, when she left her career in journalism to travel the country as a public speaker.

Title page of Ida Tarbell’s groundbreaking The History of the Standard Oil Company, originally issued as a 19-part series in McClure’s Magazine. The book version filled two fat volumes, but was such a captivating inside story of industrial greed that it became a bestseller. Library of Congress LC-USZ62-51280