* 1939 – 1945, the Second Battle of the Atlantic.

Subsequent formalizations were framed as attempts to define " effective calculability " or " effective method "; those formalizations included the Gödel – Herbrand – Kleene recursive functions of 1930, 1934 and 1935, Alonzo Church's lambda calculus of 1936, Emil Post's " Formulation 1 " of 1936, and Alan Turing's Turing machines of 1936 – 7 and 1939.

* 1890 – Anthony Fokker, Dutch aviation engineer ( d. 1939 )

* 1939 – André Ouellet, French-Canadian politician

* 1852 – Ferdinand von Lindemann, German mathematician ( d. 1939 )

* 1939 – Alan Ayckbourn, English writer

* 1939 – Johnny Raper, Australian rugby league footballer

* 1939 – The 1939-40 New York World's Fair opens.

* 1939 – NBC inaugurates its regularly scheduled television service in New York City, broadcasting President Franklin D. Roosevelt's N. Y. World's Fair opening day ceremonial address.

* 1939 – First flight of the turbojet-powered Heinkel He 178, the world's first jet aircraft.

* 1939 – William Least Heat-Moon, American author

* 1939 – Edward Patten, American singer-songwriter and producer ( Gladys Knight & the Pips ) ( d. 2005 )

* 1939 – Bulle Ogier, French actress

* 1939 – Romano Prodi, Italian politician and statesman

* 1939 – Hércules Brito Ruas, Brazilian footballer

* 1939 – Albert Einstein and Leó Szilárd write a letter to Franklin D. Roosevelt, urging him to begin the Manhattan Project to develop a nuclear weapon.

* 1939 – Benjamin Barber, American theorist

* 1939 – Wes Craven, American director

* 1939 – John W. Snow, American politician, 73rd United States Secretary of the Treasury

* 1984 – Marvin Gaye, American singer ( The Moonglows ) ( b. 1939 )

* 2001 – Trinh Cong Son, Vietnamese composer ( b. 1939 )

Eastern European theorists include Pyotr Stolypin ( 1862 – 1911 ) and Alexander Chayanov ( 1888 – 1939 ) in Russia ; Adolph Wagner ( 1835 – 1917 ), and Karl Oldenberg in Germany, and Bolesław Limanowski ( 1835 – 1935 ) in Poland.

Van Vogt's first published SF story, " Black Destroyer " ( Astounding Science Fiction, July 1939 ), was inspired by Voyage of the Beagle by Charles Darwin.

* 1851 – Charles Barrois, French geologist ( d. 1939 )

* Karl Brandi, The Emperor Charles V, 1939, pp185 – 8

* 1862 – Charles M. Schwab, American steel magnate ( d. 1939 )

* Esdaile, Charles J. Spain in the Liberal Age: From Constitution to Civil War, 1808 – 1939 ( 2000 ) excerpt and text search

* 1865 – Charles Horace Mayo, American surgeon, founder of the Mayo Clinic ( d. 1939 )

* Charles Horace Mayo ( 1865 – 1939 ), physician and co-founder of the Mayo Clinic

* 1873 – Charles Walgreen, American entrepreneur ( d. 1939 )

In April 1939, after the submission of Charles Maurras and the intervention of the Carmel of Lisieux, Pius XII ended his predecessor's ban on Action Française, an organization described by some authors as virulently antisemitic and anti-Communist.

* 1939 – Charles Geschke, American businessman, co-founded Adobe Systems

* 1854 – Charles Tatham, American fencer ( d. 1939 )

* 1936 – 1939 Charles Galton Darwin

* 1939 – 1950 Charles Raven

* October 9 – Charles Rudolph Walgreen, American businessman ( d. 1939 )

* February 19 – Charles Alexander Eastman, Native American author, physician, reformer, helped found the Boy Scouts of America ( d. 1939 )

* April 21 – Charles Barrois, French geologist ( d. 1939 )

Appleton was born in Los Angeles, California on January 4, 1939 to Jewish parents: Helen Jacobs Appleton ( born Philadelphia, 1908 ) and Charles Leonard Appleton ( born Haim Eppel Boim in Kishenov, Moldavia, 1900 ).

In 1939 the Carnegie Institution assigned Dr. Charles S. Piggot the mission of exploring the sea bed for Radium deposits.

In 1948, Charles Winters, Al Schwimmer and Herman Greenspun were convicted under the 1939 Act after smuggling B-17 Flying Fortress bombers from Florida to the nascent state of Israel during the 1948 Arab – Israeli War.

* IEEE Charles LeGeyt Fortescue Graduate Scholarship was established by the IRE in 1939 to commemorate Charles Legeyt Fortescue's contributions to electrical engineering.

Ruggles of Red Gap was adapted as a radio play on the July 10, 1939 episode of Lux Radio Theater, the December 17, 1945 episode of The Screen Guild Theater and the June 8, 1946 episode of Academy Award Theater, all with Charles Laughton and Charlie Ruggles reprising their film parts.

Love Affair is a 1939 American romantic film starring Irene Dunne and Charles Boyer and featuring Maria Ouspenskaya.

The film was Hitchcock's second Hollywood production since leaving the United Kingdom in 1939 ( the first was Rebecca ) and had an unusually large number of writers: Robert Benchley, Charles Bennett, Harold Clurman, Joan Harrison, Ben Hecht, James Hilton, John Howard Lawson, John Lee Mahin, Richard Maibaum, and Budd Schulberg, with Bennett, Benchley, Harrison, and Hilton the only writers credited in the finished film.