Ida Tarbell’s generation called her a “muckraker” (the term was Theodore Roosevelt’s, and he didn’t intend it as a compliment), but in our time she would have been known as an investigative reporter, with the celebrity of Woodward and Bernstein. By any description, Ida Tarbell was one of the most powerful women of her time in the United States: admired, feared, hated. When her History of the Standard Oil Company was published, first in McClure’s Magazine and then as a book (1904), it shook the Rockefeller interests, caused national outrage, and led the Supreme Court to fracture the giant monopoly into several corporations, one of which survives today as ExxonMobil.