Charles Otis Whitman was an extremely curious and driven researcher who was not content to limit himself to one field of expertise. Among the fields of study to which he made significant contributions were: embryology; morphology, or the form of living organisms and the relationships between their structures; natural history; and behavior. Whitman served as director of several programs and institutions, including the Biology Department at the University of Chicago, where he helped establish a new style of biology and influenced the work of many researchers of his generation, as well as future ones. He also served as first director of the Marine Biological Laboratory (MBL) in Woods Hole, MA. Besides his considerable achievements with his own scientific research, Whitman was a tireless mentor who had many students who went on to achieve great success in the field of embryology.