By the early 1900s,John D. Rockefeller, Sr. had finished building his oil empire. For over 30 years, he had applied his uncanny shrewdness, thorough intelligence, and patient vision to the creation of an industrial organization without parallel in the world. The new century found him facing his most formidable rival ever -- not another businessman, but a 45-year-old woman determined to prove that Standard Oil had never played fair. The result, Ida Tarbell's magazine series "The History of the Standard Oil Company," would not only change the history of journalism, but also the fate of Rockefeller's empire, shaken by the powerful pen of its most implacable observer.

Born in a log home in Hatch Hollow, northwestern Pennsylvania, on November 5, 1857, Ida Minerva Tarbell grew up amid the derricks of the Oil Region. Her father, Frank Tarbell, built wooden oil storage tanks and later became an oil producer and refiner. "Things were going well in father's business," she would write years later. "There was ease such as we had never known; luxuries we had never heard of. ...Then suddenly [our] gay, prosperous town received a blow between the eyes." The 1872 South Improvement scheme, a hidden agreement between the railroads and refiners led by John D. Rockefeller, hit the Pennsylvania Oil Region like a tidal wave. It hit the Tarbells too, leaving behind painful memories that would be rekindled 30 years later. "Out of the alarm and bitterness and confusion, I gathered from my father's talk a conviction to which I still hold -- that what had been undertaken was wrong."

After graduating from Allegheny College, the sole woman in the class of 1880, Tarbell moved to Ohio to teach science, but resigned after two years. She would find her true calling just months later back in Pennsylvania, when she met the editor of a small magazine, The Chautauquan, published in Meadville, Pennsylvania. Tarbell’s inquisitive mind and her determination to have a career pushed her to become intensely invested in her writing and research projects. At 34, fascinated by the story of Madame Roland, the leader of an influential salon during the French Revolution, she moved to Paris to write her biography.

Overseas, Tarbell supported herself by writing numerous articles on the City of Light for the popular magazines of the day. It was this work that got the attention of editor Samuel Sidney McClure, then looking for writers for his new monthly. Tarbell was hired as an editor in 1894, and soon became McClure's Magazine's most successful writer when her series on Abraham Lincoln nearly doubled the circulation of the magazine. Another serialized biography followed, this time on Napoleon, establishing her as a gifted historical writer and an insightful judge of character.

But events and trends far more immediate were calling for attention. The rapidly changing economic landscape and the rise of monopolistic trusts was "disturbing and confusing people," wrote Tarbell. A new generation of investigative journalists, later dubbed "muckrakers" by President Theodore Roosevelt, had set out to wage a campaign to expose corruption in business and political lawlessness. Tarbell latched onto the idea of using the story of Standard Oil to illustrate these troubling issues, persuading McClure to agree to a three-part series on the oil trust.

Tarbell's father, fearing that Rockefeller would retaliate against the magazine, advised her not to do it. But she dove into the work with a zeal that matched her antagonist’s. For almost two years, she painstakingly looked through volumes of public records, including court testimony, state and federal reports and newspaper coverage. From these, she gathered a mind-boggling wealth of information on Rockefeller's ascent and the methods used by Standard Oil. The breadth of her research was remarkable, but even more impressive was her ability to digest Rockefeller's complicated business maneuvers into a narrative that would be accessible and engaging to the average reader.

Although always modest about her prose, Tarbell was an eloquent writer, able to combine her keen analytical skills with a sense of drama. "Now, it takes time to secure and to keep that which the public has decided it is not for the general good that you have," she wrote in July of 1903. "It takes time and caution to perfect anything which must be concealed. It takes time to crush men who are pursuing legitimate trade. But one of Mr. Rockefeller's most impressive characteristics is patience. There never was a more patient man, or one who could dare more while he waited. … He was like a general who, besieging a city surrounded by fortified hills, views from a balloon the whole great field, and sees how, this point taken, that must fall; this hill reached, that fort is commanded. And nothing was too small: the corner grocery in Browntown, the humble refining still on Oil Creek, the shortest private pipe line. Nothing, for little things grow."

Instantly popular with readers, "The History of the Standard Oil Company" grew to be a 19-part series, published between November 1902 and October 1904. Tarbell wrote a detailed exposé of Rockefeller's unethical tactics, sympathetically portraying the plight of Pennsylvania's independent oil workers. Still, she was careful to acknowledge Rockefeller's brilliance and the flawlessness of the business structure he had created. She did not condemn capitalism itself, but "the open disregard of decent ethical business practices by capitalists." About Standard Oil, she wrote: "They had never played fair, and that ruined their greatness for me."

Tarbell capped the series with a two-part character study that revealed her fixation with the man she had been studying for the better part of five years. Focusing on Rockefeller's weary appearance, she called him "the oldest man in the world -- a living mummy," and accused him of being "money-mad" and "a hypocrite." "Our national life is on every side distinctly poorer, uglier, meaner, for the kind of influence he exercises," she concluded. Rockefeller was deeply hurt by this last attack from "that poisonous woman," as he called her, but he refused to engage in any public rebuttal of her allegations. "Not a word," he told his advisors. "Not a word about that misguided woman."

"The History of the Standard Oil Company" would be hailed as a landmark in the history of investigative journalism, as well as the most comprehensive study of the building of Rockefeller's oil empire. In 1999, it was listed number five among the top 100 works of 20th-century American journalism.

Having become one of the most influential women in the country, Ida Tarbell went on to pursue numerous writing and lecturing engagements. However, she rejected the status of role model. In spite of her accomplishments as a woman working at the turn of the century, she opposed the suffrage movement, arguing that traditional female roles had been belittled by women's rights advocates and that women's contributions belonged in the private sphere. She died of pneumonia in 1944, at the age of 86.