Robert Millikan was an American physicist born on March 22, 1868, in Morrison, Illinois. He is best known for his work on the photoelectric effect and for measuring the charge of the electron through his famous oil drop experiment. Millikan's research significantly advanced the understanding of atomic structure and earned him the Nobel Prize in Physics in 1923. In addition to his scientific contributions, Millikan served as a professor at the California Institute of Technology and became its first president. He was also involved in various educational and scientific organizations, promoting the importance of science in society throughout his career.