Biography:

 Crawford Hallock Greenewalt (August 16, 1902 – September 28, 1993) , son of Mary Hallock Greenewalt and Frank Lindsey Greenewalt, was an American chemical engineer who served as president of the DuPont Company from 1948 to 1962 and as board chairman from 1962 to 1967.
Greenewalt was born in Cummington, Massachusetts. In 1922 he earned a Bachelor of Science degree in chemical engineering from Massachusetts Institute of Technology, where he joined Theta Chi Fraternity. He later became a Life Member of the MIT Corporation in 1951, and emeritus in 1977.
Greenewalt had two sons, Crawford "Greenie" Greenewalt Jr. (1937-2012) and David Greenewalt, and daughter, Nancy L. Frederick. The younger Crawford was a professor of classical archaeology at the University of California, Berkeley who was among the leaders of the Archaeological Exploration of Sardis. David died in 2003.
While at DuPont, Greenewalt was a key figure in their development of nylon and their nuclear power program.
His widely varied interests included ornithology and high-speed photography via his friend Harold E. "Doc" Edgerton Greenewalt published a book of 70 high-speed photographs of hummingbirds in 1960. In 1968 he published Bird Song: Acoustics and Physiology. He also served as president of the American Philosophical Society.