At the end of the 19th century, when most women stayed at home, Ida Tarbell went to work. Most working women in those days were nurses or teachers, so she tried teaching briefly, but she ended up as a writer. Back then, the few women in media handled the society pages, but Tarbell had other ideas. Along with a few male colleagues, in a group that collectively became known as the muckrakers, she emerged as one of America’s earliest and finest investigative reporters.

Tarbell was born in western Pennsylvania, where — the only woman in the class of 1880 — she received A.B. and M.A. degrees from Allegheny College. In 1891 she moved to Paris, continuing her studies at the Sorbonne while supporting herself as a journalist. Three years later, back in America, she was approached by the editor S. S. McClure, who asked her to write about Napoleon for his eponymous magazine.

Tarbell worked at McClure’s for the next 12 years, next doing a biographical series on Abraham Lincoln. From November 1902 to October 1904 the magazine printed her most important work, a 19-part series that became The History of the Standard Oil Company. These two volumes, still one of the most thorough investigations ever written of how a business monopoly exploits the public by using unfair tactics, has been called by Daniel Yergin “arguably… the single most influential book on business ever published in the United States.” Its publication led to the company’s break-up in 1911 following prosecutions under the Sherman Anti-Trust Act.

In 1906, Tarbell, along with fellow investigative reporters Lincoln Steffens and Ray Stannard Baker, left McClure’s and bought the American Magazine, which she co-edited and wrote for until 1915. Later in life, she became a popular lecturer for almost 20 years on the Chautauqua circuit, and also wrote many other books, including nine about Lincoln. Her autobiography, All in the Day’s Work, was published in 1939.

In 1922, The New York Times named Tarbell one of the 12 most important women in America. In 1999, her series on Standard Oil was voted 5th on the 100 most important works of journalism in the 20th century. She was inducted into the National Women’s Hall of Fame in 2000, and honored with her own postage stamp in 2002.