* 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.

* 1939 – Roy Romanow, Canadian politician

* 1885 – Édouard Fabre, Canadian runner ( d. 1939 )

* 1939 – Lise Thibault, Canadian civil servant, 27th Lieutenant Governor of Quebec

* 1939 – Red Berenson, Canadian ice hockey player

* 1939 – Francis Fox, Canadian politician, member of the Senate

* 1939 – Jean Beaudin, Canadian film director and screenwriter

* 1939 – Raôul Duguay, Canadian artist, poet, musician, and political activist

* John Ford Messer ( 1889 – 1949 ), Canadian local-level legislator ; served as Conservative member of New Brunswick Legislative Assembly from 1939 to 1944

* 1939 – Anne Heggtveit, Canadian alpine skier

* 1939 – J. C. Tremblay, Canadian ice hockey player ( d. 1994 )

* 1939 – Cesare Maniago, Canadian ice hockey player

* 1939 – Gordon O ' Connor, Canadian politician

* 1939 – Sidney Altman, Canadian biologist, Nobel laureate

* 1939 – Bill Graham, Canadian politician

* 1939 – Margaret Atwood, Canadian poet, novelist, critic and essayist

* 1939 – Norman Bethune, Canadian doctor and humanitarian ( b. 1890 )

* 1861 – James Naismith, Canadian inventor of basketball ( d. 1939 )

* 1939 – Robin Spry, Canadian filmmaker and producer ( d. 2005 )

* 1939 – Len Cariou, Canadian actor

First lady Dolley Madison rescued a painting of George Washington, and in 1939, a Canadian man returned a jewelry box to President Franklin Delano Roosevelt, claiming that his grandfather had taken it from Washington.

His government also made the Canadian Broadcasting Corporation a crown corporation in 1936, created Trans-Canada Airlines ( the precursor to Air Canada ) in 1937, and formed the National Film Board of Canada in 1939.

In the lead-up to World War II in 1939, King affirmed Canadian autonomy by saying that the Canadian Parliament would make the final decision on the issue of going to war.

" Double Vision: Ernest Lapointe, Mackenzie King and the Quebec Voice in Canadian Foreign Policy, 1935-1939 ," Journal of Canadian Studies 1999 34 ( 1 ): 93-111 ; argues Lapointe guided the more imperialist Mackenzie King through three explosive situations: the Ethiopian crisis of 1935, the Munich crisis of 1938, and the formulation of Ottawa's ' no-neutrality-no-conscription ' pact in 1939.