The Oldstone Conference of 11 to 14 April 1949 was the third of three postwar conferences held to discuss quantum physics; arranged for the National Academy of Sciences

United States National Academy of Sciences

The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...

 by J. Robert Oppenheimer, who was again chairman. It followed the Shelter Island Conference

Shelter Island Conference

The first Shelter Island Conference on the Foundations of Quantum Mechanics was held from June 2–4, 1947 at the Ram's Head Inn in Shelter Island, New York. Shelter Island was the first major opportunity since Pearl Harbor and the Manhattan Project for the leaders of the American physics community...

 of 1947 and the Pocono Conference

Pocono Conference

The Pocono Conference of 30 March to 2 April 1948 was the second of three postwar conferences held to discuss quantum physics; arranged by Robert Oppenheimer for the National Academy of Sciences...

 of 1948. There were 24 participants; new participants were Robert Christie

Robert Christie

Robert Christie was a lawyer, journalist, historian and political figure in Lower Canada and Canada East....

, Freeman Dyson

Freeman Dyson

Freeman John Dyson FRS is a British-born American theoretical physicist and mathematician, famous for his work in quantum field theory, solid-state physics, astronomy and nuclear engineering. Dyson is a member of the Board of Sponsors of the Bulletin of the Atomic Scientists...

 (whose writings explained Feynman’s ideas), George Placzek

George Placzek

Georg Placzek was a Czech physicist.Born in Brno, Moravia, Placzek studied physics in Prague and Vienna. He worked with Hans Bethe, Edward Teller, Rudolf Peierls, Werner Heisenberg, Victor Weisskopf, Enrico Fermi, Niels Bohr, Lev Landau, Edoardo Amaldi, Emilio Segrè, Leon van Hove and many other...

, and Hideki Yukawa

Hideki Yukawa

né , was a Japanese theoretical physicist and the first Japanese Nobel laureate.-Biography:Yukawa was born in Tokyo and grew up in Kyoto. In 1929, after receiving his degree from Kyoto Imperial University, he stayed on as a lecturer for four years. After graduation, he was interested in...

.

Held at Oldston-on-the-Hudson in Peekskill, New York

Peekskill, New York

Peekskill is a city in Westchester County, New York. It is situated on a bay along the east side of the Hudson River, across from Jones Point.This community was known to be an early American industrial center, primarily for its iron plow and stove products...

, the main talking-point was Richard Feynman

Richard Feynman

Richard Phillips Feynman was an American physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics...

’s approach to quantum electrodynamics (QED); Feynman was now (at 30) the leading physicist of his generation.