Engineers and computer scientists

Leo Breiman

Leo Breiman (1928–2005) was an American statistician and professor at the University of California, Berkeley, who created bagging and Random Forests, co-created CART, and won the 2005 ACM SIGKDD Innovation Award.

Leo R. Beard

Leo Roy Beard (1917–2009) was an American civil engineer and hydrologist who coined the term hydrologic engineering, founded the Corps' Hydrologic Engineering Center, and was elected to the National Academy of Engineering in 1975.

Leo Young (electrical engineer)

Leo Young (1926–2006) was an Austrian-born American electrical engineer who led microwave filter research at Stanford Research Institute, directed research at the Pentagon, and co-authored the 1964 filter handbook.

Léon Charles Thévenin

Léon Charles Thévenin was a French telegraph engineer who published Thévenin's theorem in 1883, letting a linear circuit be replaced by a voltage source and resistance.

Leon K. Kirchmayer

Leon K. Kirchmayer (1924–1995) was an American electrical engineer at General Electric, elected to the National Academy of Engineering in 1979 for power-system control and planning.

Leonard Adleman

Leonard Adleman, born 1945, is an American computer scientist at the University of Southern California who co-invented the RSA cryptosystem in 1977 and founded DNA computing in 1994.

Leonard Cutler

Leonard Cutler (1928–2006) was an American physicist who cofounded HP Labs and led development of the HP 5060A and 5071A cesium atomic clocks, whose 5071A remains the largest contributor of cesium clocks to Coordinated Universal Time.

Leonard F. Fuller

Leonard F. Fuller (1890–1987) was an American electrical engineer who, as chief engineer of the Federal Telegraph Company, developed high-power Poulsen arc transmitters used by the United States Navy for long-distance radio telegraphy.

Leonard J. Koch

Leonard J. Koch (1920–2015) was an American nuclear engineer who served on EBR-I, the first reactor to generate electricity, and managed its successor EBR-II at Argonne.

Leonard Kleinrock

Leonard Kleinrock, born 1934, is an American computer scientist at UCLA whose mathematical theory of packet switching underpinned the Internet; his lab sent the first ARPANET message in 1969.

Leonard Pinchuk

Leonard Pinchuk is a biomedical engineer and inventor at the University of Miami, elected to the National Academy of Engineering in 2012 and known for the polymer SIBS and the TAXUS drug-eluting stent.

Leonardo de Moura

Leonardo de Moura is a Brazilian computer scientist who created the Z3 SMT solver and Lean theorem prover, and co-founded the Lean FRO at AWS.

Leonid Levin

Leonid Anatolievich Levin (Леони́д Анато́льевич Ле́вин) is a Soviet-born American computer scientist at Boston University who independently discovered NP-completeness alongside Stephen Cook and won the 2012 Knuth Prize.

Leonid Rudin

Leonid (Lenny) Rudin is an American computer scientist, co-author of the landmark 1992 Rudin–Osher–Fatemi total-variation denoising paper and co-founder and CEO of Cognitech, a Santa Monica forensic video analysis firm.

Leonidas Guibas

Leonidas Guibas is a Stanford computer scientist known as a founder of computational geometry, for the quad-edge data structure, and for shape analysis and geometric deep learning.

Leopold Aschenbrenner

Leopold Aschenbrenner is a German-born investor and former OpenAI safety researcher who wrote the 2024 essay Situational Awareness and founded the hedge fund Situational Awareness LP.

Leopold Godowsky Jr.

Leopold Godowsky Jr. (1900–1983) was an American concert violinist and photographic chemist who, with Leopold Mannes, codeveloped Kodachrome, the first practical color transparency film, introduced in 1935.

Leopold Mannes

Leopold Mannes (Leopold Damrosch Mannes, 1899–1964) was an American pianist and composer who co-invented Kodachrome, the first practical color transparency film, with Leopold Godowsky Jr.

Leroy H. Smith Jr.

Leroy Harrington Smith Jr., known professionally as Roy Smith, was an American mechanical engineer and pioneer of modern turbomachinery aerodynamics who spent his career at General Electric in Evendale, Ohio.

Leslie A. Geddes

Leslie A. Geddes (1921–2009) was a Scottish-born American biomedical engineer and physiologist at Purdue University whose defibrillation and electrode research earned the 2006 National Medal of Technology.

Leslie A. Momoda

Leslie A. Momoda is an American materials scientist and Executive Vice President of HRL Laboratories in Malibu, California, elected to the National Academy of Engineering in February 2025.

Leslie E. Robertson

Leslie E. Robertson (1928–2021) was an American structural engineer best known as lead engineer of the World Trade Center twin towers, completed in 1972 and 1973.

Leslie L. Shoemaker

Leslie L. Shoemaker is an American water resources engineer and Tetra Tech executive elected to the National Academy of Engineering in 2022 for watershed management technology.

Leslie Lamport

Leslie Lamport, born 1941 in New York City, is an American computer scientist who developed LaTeX and won the 2013 ACM Turing Award for work on distributed systems.

Leslie P. Kaelbling

Leslie Pack Kaelbling is the Panasonic Professor of Computer Science at MIT, known for reinforcement learning and POMDP research and for founding the Journal of Machine Learning Research.

Leslie Valiant

Leslie Valiant, born 1949, is a Harvard computer scientist who founded computational learning theory, defined the counting class #P, and shaped parallel computing, winning the 2010 Turing Award.

Lester A. Hoel

Lester A. Hoel (1935–2022) was an American transportation engineer, a University of Virginia professor and National Academy of Engineering member who co-authored Traffic and Highway Engineering.

Lester F. Eastman

Lester F. Eastman (1928–2013) was an American electrical engineer at Cornell University who built the first US university research program on compound-semiconductor microwave devices such as gallium arsenide.

Lester Hogan

C. Lester Hogan (1920–2008) was an American physicist and semiconductor executive who invented the microwave gyrator at Bell Labs, taught at Harvard, and led Motorola Semiconductor and Fairchild.