Ida M. Tarbell Investigative journalist Ida Tarbell, shown in her home office in 1905, exposed the ruthless business practices that John D. Rockefeller used to create and run his Standard Oil Company. Tarbell was one of the Progressive Era’s muckrakers, who published articles in popular magazines and wrote books that evoked public outrage and calls for reform. The Ida M. Tarbell Collection, Pelletier Library, Allegheny College