Brockway McMillan (March 30, 1915 – December 3, 2016) was an American government official and scientist, who served as the eighth Under Secretary of the Air Force and the second Director of the National Reconnaissance Office.

in 1936 and a Ph.D. 1939 from Massachusetts Institute of Technology (MIT) on a thesis entitled The calculus of discrete homogenous chaos supervised by Norbert Wiener.

He joined Bell Telephone Laboratories 1946 as a research mathematician and published the article "The Basic Theorems of Information Theory"[5] and proved parts of Kraft's inequality, sometimes called the Kraft-McMillan theorem (Kraft proved that if the inequality is satisfied, then a prefix code exists with the given lengths.

)[6] McMillan served as the President of the Society for Industrial and Applied Mathematics (SIAM) 1959-1960.

[9] In 1942, while at Princeton University, McMillan married Elizabeth Audrey Wishard (1915–2008) who had a PhD in mathematics from Radcliffe College in Cambridge, Boston, in 1938.