Harvey Douglas Keith (10 March 1927 – 9 February 2003) was a physicist and one of the primary polymer researchers over the latter half of the 20th century.

[1][2] Keith immigrated to the United States in 1956 after accepting a position at the American Viscose Corporation in Marcus Hook, Pennsylvania, where he began researching the complex structures and morphologies of macromolecules.

[1] Forming the basis of what has become known as the Keith and Padden theory, the two researchers published "Twisting orientation and the role of transient states in polymer crystallization"[4] in 1984 and "Banding in Polyethylene and other spherulites"[5] in 1996.

These two papers addressed the long-standing problem of accounting for the origins of lamellar (a thin layer) twisting in banded polymer spherulites.

[6] After his retirement from Bell Labs in 1988, Keith continued his polymer morphology research as a faculty member at the University of Connecticut.