Simon Flexner was a physician, scientist, administrator, and professor of experimental pathology at the University of Pennsylvania (1899–1903). He served as the first director of the Rockefeller Institute for Medical Research (1901–1935) and a trustee of the Rockefeller Foundation. He was also a friend and adviser to John D. Rockefeller Jr.

The Rockefeller University is a private biomedical research and graduate-only university in New York City, New York. It focuses primarily on the biological and medical sciences and provides doctoral and postdoctoral education. It is classified as a "Special Focus – Research Institution". Rockefeller is the oldest biomedical research institute in the United States.