Parry Moon

Parry Hiram Moon (; February 14, 1898 – March 4, 1988) was an American electrical engineer who, with Domina Eberle Spencer, co-wrote eight scientific books and over 200 papers on subjects including electromagnetic field theory, color harmony, nutrition, aesthetic measure and advanced mathematics. He also developed a theory of holors.

Biography Moon was born in Beaver Dam, Wisconsin, to Ossian C. and Eleanor F. (Parry) Moon. He received a BSEE from University of Wisconsin in 1922 and an MSEE from MIT in 1924. Unfulfilled with his work in transformer design at Westinghouse, Moon obtained a position as research assistant at MIT under Vannevar Bush. He was hospitalized for six months after sustaining injuries from experimental work in the laboratory. He later continued his teaching and research as an associate professor in MIT's Electrical Engineering Department. He married Harriet Tiffany, with whom he had a son. In 1961, after the death of his first wife, he married his co-author, collaborator and former student, Domina Eberle Spencer, a professor of mathematics. They had one son. Moon retired from full-time teaching in the 1960s, but continued his research until his death in 1988.

Scientific contributions Moon's early career focused in optics applications for engineers. Collaborating with Spencer, he began researching electromagnetism and Amperian forces. The quantity of papers that followed culminated in Foundations of Electrodynamics, unique for its physical insights, and two field theory books, which became standard references for many years. Much later, Moon and Spencer unified the approach to collections of data (vectors, tensors, etc.), with a concept they coined "holors". In modern parlance, holors are precisely multidimensional arrays of real numbers, and the terminology of holors is very rarely encountered. See the appendix of for a concise description of holors.