Harry Leslie Van Trees (June 27, 1930 – December 29, 2022) was an American scientist specializing in radar, sonar, communications and signal processing.

[4] While working at Massachusetts Institute of Technology (MIT) during 1968-1971, Van Trees published a three-volume series of textbooks on the detection, estimation, and modulation theory.

"[8] In addition to academic work, Van Trees has also assisted with the implementation of theory into practice in several Department of Defense positions.

Additionally, Van Trees was the Assistant Secretary of Defense for Networks and Information Integration; Command, Control, Communications and Intelligence (C3I).

[8][9] From 1982-1988, Van Trees ran the Eastern Operations of M/A-Com Linkabit, a company founded by Irwin M. Jacobs and Andrew Viterbi.

In 1987, Van Trees joined George Mason University (GMU) as a Distinguished Professor of Information Technology, and Electrical and Systems Engineering.