John D. Rockefeller

After beginning his life in poor circumstances, John Rockefeller rose to control the booming petroleum industry by the age of 40. He became the wealthiest man of his day, and he has a strong claim to be the wealthiest self-made individual who ever lived. Rockefeller's net worth peaked at nearly 1.5 percent of the country's entire yearly economic output, the equivalent of about $280 billion today, or roughly three times Bill Gates' wealth.

He was also a well-known philanthropist. He gave extraordinary resources to charity as a natural businessman with a strong moral sensibility and passionate religious convictions. During his lifetime, Rockefeller helped to establish the area of biomedical research by supporting scientific studies that resulted in vaccinations for diseases such as meningitis and yellow fever. He transformed medical education in the United States and established China's first proper medical school. He championed the cause of public sanitation, founding public health institutions at Johns Hopkins and Harvard, and assisting in the leadership of significant international public-health initiatives against hookworm, malaria, yellow fever, and other illnesses.

He passionately championed the cause of education across the country, regardless of gender, ethnicity, or belief. He built the University of Chicago from the ground up and transformed it into one of the world's leading universities in less than a decade.