* 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.

The laboratory was founded as the Radiation Laboratory of the University of California, associated with the Physics Department, on August 26, 1931 by Ernest Orlando Lawrence as a site for centering physics research around his new instrument, the cyclotron ( a type of particle accelerator for which he won the Nobel Prize in Physics in 1939 ).

* Orlando ( the Marmalade Cat ): A Trip Abroad ( 1939 )

In 1939, Carr ( then a businessman ) organized the Community Chest of Orlando, the community's first annual fund drive conducted to support local charitable organizations and the forerunner of the Heart of Florida United Way organization.

Orlando Parga Figueroa ( born on February 6, 1939 in Mayagüez, Puerto Rico ) is a Puerto Rican politician and former member of the Senate of Puerto Rico.

Orlando Parga Figueroa was born on February 6, 1939 in Mayagüez, Puerto Rico.

Puerto Rican leaders had lobbied for such an opportunity repeatedly, in 1898, 1912, 1914, 1919, 1923, 1929, 1932, 1939, 1943, 1944, 1948, 1956, and 1960.

Rubén Ángel Berríos Martínez ( born June 21, 1939 ) is a Puerto Rican lawyer and politician, and the current president of the Puerto Rican Independence Party ( PIP ).

Hermes Davide Fastino Croatto Martinis, better known as Tony Croatto ( March 2, 1940, some sources state his year of birth as 1939 – April 3, 2005 ) was an Italian singer and composer best known for his interpretations of Puerto Rican folk music.

Gruening was appointed to the U. S. delegation to the 7th Inter-American Conference in 1933, Director of the Division of Territories and Island Possessions of the Department of the Interior, 1934 – 1939, Administrator of the Puerto Rico Reconstruction Administration, 1935 – 1937.

In 1939, he married Puerto Rican Arah Mina López, a journalist who joined him as he returned to Cuba in 1939.

From left to right, José Gonzalez, Grover Whalen, and Dennis Nolan looking over plans for the Puerto Rico pavilion at the 1939 World's Fair.

In 1939, the Puerto Rican Department was created and in May 1941 the Panama Canal and Puerto Rican Departments were combined as the Caribbean Defense Command, although each was still referred to as a department.

Frankie Narvaez ( December 3, 1939 – April 15, 2004 ) was a Puerto Rican boxer.

González was born in 1939 in the center of the island of Puerto Rico, in the small town of Lares.

Miguel Ángel Suárez ( July 5, 1939 – April 1, 2009 ) was a Puerto Rican soap opera and movie actor.

Santiago Iglesias Pantín ( February 22, 1872 – December 5, 1939 ), a supporter of statehood for Puerto Rico, was the Resident Commissioner of Puerto Rico in the U. S. Congress from 1933 to 1939, a period that saw significant political turbulence in Puerto Rico, both by Puerto Ricans seeking more freedom and autonomy, and by the military governor in the Island, Blanton Winship, seeking to clamp down on those seeking autonomy and independence.

Iglesias died in office in Washington, D. C. on December 5, 1939 and his body was returned home to Puerto Rico, where it lay in state at the Capitol.

First International game: On 9 April 1939 against Costa Rican side Orión F. C.

Dr. Antonio S. Pedreira ( June 13, 1899 – October 23, 1939 ), was a renowned Puerto Rican author and educator.

Antonio (" Toño ) Martorell Cardona ( born 1939 ) is a Puerto Rican painter, graphic artist, writer and radio and television personality.

* Miguel Ángel Suárez ( 1939 – 2009 ), Puerto Rican film actor

José Alberto " Coco " Laboy ( born July 3, 1939 ) is a former Puerto Rican Major League Baseball player.

* Rolando Cruz ( 1939 –), Puerto Rican pole vaulter