Henry DeWolf "Harry" Smyth (/ˈhɛnri dəˈwʊlf ˈsmaɪθ/; May 1, 1898 – September 11, 1986) was an American physicist, diplomat, and bureaucrat.

[8] Smyth earned a master's degree and PhD in physics from Princeton in 1920 and 1921, respectively, studying under Karl Taylor Compton.

The U.S. National Research Council awarded Smyth a fellowship, and he joined the Cavendish Laboratory at the University of Cambridge.

[11] During World War I, Smyth worked in the Chemical Warfare Service,[12] and at the Aberdeen Proving Ground.

During 1931–32 he was a Guggenheim Fellow at the University of Göttingen,[5] where he studied the spectra of triatomic molecules, particularly carbon dioxide, with James Franck.

[23] As Robert H. Dicke, Val Logsdon Fitch, and Rubby Sherr wrote in 1989, "By 1935 his 30 published papers established him as a leading experimentalist" in the field.

[7] In 1929 Kenneth Bainbridge completed his PhD dissertation at Princeton working under Smyth, using anode rays to search for element 87.

[5] Richard Feynman had achieved an unprecedented perfect score on the Princeton University entrance exams, and applied for admission.

While department chair, Smyth questioned his admission, writing to Philip M. Morse to ask: "Is Feynman Jewish?

[26] During World War II, Smyth was involved in helping the United States build the atomic bomb.

[28] He remained chairman of Princeton's physics department throughout the war, and the attendant obligations forced him to participate less actively in the project's later stages.

The committee recommended that a national commission modeled on the OSRD fund and oversee continued production and fundamental research in government laboratories, universities, and the private sector.

Smyth held the copyright to the work to prevent others from claiming it, but he permitted widespread reproduction, essentially releasing it into the public domain.

During this time he spoke and wrote regularly about nuclear energy and science policy[5] and worked to expand the physics department.

He and AEC Chairman David Lilienthal wanted a physicist to replace Bacher, and they ultimately recommended Smyth for the position.

Led by Senator Bourke Hickenlooper, the hearings inquired into a small amount of uranium that was alleged to be unaccounted for in AEC labs.

[38] The AEC's nine-member General Advisory Committee, chaired by J. Robert Oppenheimer, recommended unanimously in October 1949 against such a course.

[5] Smyth became a supporter of the weapon,[44] and in February 1950, endorsed a specific program for the future production of H-bombs.

[46] Indeed, by the time of that test Smyth was looking for ways to use a successful thermonuclear explosion's psychological impact to benefit American foreign policy aims.

[44] Urged by a journal editor to publish his recollections of the H-bomb decision, Smyth drafted several attempts at an article but eventually abandoned it.

Hall served as principal advisors to President Dwight Eisenhower in preparing his Atoms for Peace speech to the United Nations.

This work included advising on the construction of a particle accelerator built jointly with the University of Pennsylvania and overseeing Project Matterhorn, which became the Princeton Plasma Physics Laboratory.

[5] President John F. Kennedy appointed Smyth as the representative of the United States to the IAEA, a position with the rank of Ambassador.

[5] He helped develop what Glenn Seaborg later called "an unprecedented atmosphere of rapport" at the IAEA and played a crucial role in the adoption of the Nuclear Non-Proliferation Treaty in 1970.

[58] In September 1961, Harlan Cleveland, then Assistant Secretary of State for International Organization Affairs, appointed Smyth to chair a committee to review U.S. policy toward the IAEA.

During Smyth's tenure, the URA signed a contract with the U.S. government to construct and operate the National Accelerator Laboratory, which later became known as Fermilab.

On the 40th anniversary of the Trinity test in 1985, he denounced President Ronald Reagan's Strategic Defense Initiative and called for joint arms reductions between the United States and the Soviet Union.

[65] The Smyth Report has remained the most significant release of technical details regarding atomic weapons ever made.