The Smyth Report was the common name given to an administrative history written by physicist Henry DeWolf Smyth about the Allied World War II effort to develop the atomic bomb, the Manhattan Project. The full title of the report was the unwieldy Atomic Energy for Military Purposes; The Official Report on the Development of the Atomic Bomb under the Auspices of the United States Government, 1940-1945. It was released to the public on August 12, 1945, after the atomic bombings of Hiroshima and Nagasaki on August 6 and 9.
General Leslie Groves commissioned Smyth to write the Report at Los Alamos during the Manhattan Project. The Report was to serve two functions. First, it was to be the official U.S. government history and statement about the development of the atomic bombs, outlining the development of the then-secret laboratories and production sites at Los Alamos, New Mexico, Oak Ridge, Tennessee, and Hanford, Washington, and the basic physical processes responsible for the functioning of nuclear weapons, in particular nuclear fission and the nuclear chain reaction. Secondly, it serves as a barometer for other scientists as to what information was declassified—anything said in the Smyth Report could be said freely in open literature. For this reason, the Smyth Report focused heavily on information already available in declassified literature, such as much of the basic nuclear physics used in weapons, which was either already widely known in the scientific community or could have been easily deduced by a competent scientist.
The stated purpose of the Smyth Report was to give enough information to citizens so that they could understand enough about the new atomic weapons to make sensible policy decisions regarding them. From the Preface (emphasis added):
Despite undergoing extensive security review before release, the Smyth Report was criticized by politicians as having "given away the secret of the A-bomb." It was indeed used extensively in the Soviet Union to tailor their own bomb project, though only in terms of what sorts of factories to produce and to compare their progress with the scale of the American project. However, most politicians themselves knew nothing about atomic weapons, and because they did not know which "secrets" were not released by the Smyth Report, they had no idea how many "secrets" actually were released.
The Smyth Report did not contain any details on creating a functional weapon, nor any illustrations (except for a graph indicating the layers of the Fermi "pile") in its initial release. A later release included pictures of the test explosion at Trinity site, the facilities at Oak Ridge and Hanford (but not Los Alamos), and basic diagrams of nuclear fission and a few other basic concepts. It did not outline how one would actually construct an atomic bomb, gesturing only vaguely towards the Little Boy uranium bomb design, and does not hint at all towards the manner in which the plutonium bomb, like Fat Man, was designed (see nuclear weapons design for the differences in design types).
The original title of the report, before it was published in book form, was A general account of the development of methods of using atomic energy for military purposes under the auspices of the United States government, 1940-1945. There was a small difference between the original text and the version published by Princeton. Groves decided a one sentence allusion to a "poisoning" effect in the production reactors due to fission byproducts, which stopped the reaction, was sensitive, and he had it removed. This deletion was soon noticed in Russia, and acted to highlight its importance to them (for more on this incident see Rhodes, 215-217). Also, in the Princeton publication, first and middle names were added instead of the previous use of abbreviations. (For example, on the original cover it gives authorship to "H. D. Smyth")
Despite the technical nature of the work, it sold almost 127,000 copies in its first eight printings and was on the New York Times best-seller list from mid-October 1945 until late-January 1946. It has been translated into over 40 different languages.