Sixteen hours* after an atomic bomb exploded over Hiroshima, the White House released a pre-written statement under Truman's name (Truman was himself still on a boat coming back from the Potsdam Conference, and the statement had been written weeks earlier by the Vice President of Marketing for AT&T, who was a friend of the Secretary of War). The statement made very clear that a new kind of weapon had been developed and used, and gave a very broad overview of the implications of this and its history. A longer, more detailed statement soon followed, released under the name of the Secretary of War, Henry Stimson, which discussed some of the more detailed administrative arrangements. At the same time as all of this, a series of pre-written news stories, written by William Laurence of the New York Times (who had been embedded in the Manhattan Project) were released to the national press explaining what an atomic bomb was, how it was made, the various sites and personalities associated with the project, and so on.

All of this "Publicity" blitz, as the Manhattan Project principals called it, had been in the works since late 1944, when the realistic prospect of using the bomb had become more well-defined. They believed that in the absence of information, the American press would search for the story, and might find out things that they still wanted to keep secret, or would bungle it. And they also worried that without a lot of information, the American, Japanese, and global publics would not understand what had happened to the degree necessary to understand what it might mean not only for World War II, but the future of warfare.

Finally, a few days after the Nagasaki attack, Truman approved the release of the Smyth Report, a technical and administrative history of the atomic bomb that had been written by the chairman of the Princeton Physics Department, Henry DeWolf Smyth, which explained — within the constraints of carefully-constructed security rules — what the Manhattan Project was and how it functioned. The goal was to give engineers and technical-minded people enough information that they could then popularize and explain it to others, again with a dual goal of informing the democratic public discourse and maintaining security (anything not mentioned in the book, the book itself helpfully explained, should be considered still secret). The initial reserves of the report were immediately depleted, and Princeton University Press quickly put out a hardback edition. It was translated into dozens of languages almost immediately, including Russian, and for many years it was essentially the only information that a Soviet citizen could acquire about nuclear weapons.

Which is only to say, at some length, that the people who made the bomb did their best to try and publicize what the bomb was, how it was made, and how it worked. They, as we might imagine, left out quite a lot. Any information about bomb design was kept intentionally vague, and there were lots of areas where what was released was kept in the kinds of general terms that essentially any scientist could have worked out, knowing that the thing had happened and was successful.

Anyway, it is — I think — a pretty interesting story, and notably points to the idea that secrecy and revelation were considered two sides of the same coin, contrary to how we tend to think about it. For more information on the "Publicity" campaign, I would direct you to chapter 3 of my soon to be forthcoming book on the history of nuclear secrecy! :-) If you are curious about how the scientists, military, and statesmen thought about this kind of release of information, I also recently uploaded a document to the book website (under "Documents") that is the transcript of a long meeting in which the question of whether to release the Smyth Report, and the possible value of danger of doing so, was debated. It is one of my favorite documents from the book, as it gets at the heart of many tricky issues about secrecy and the bomb.

* You might reasonably ask, why sixteen hours? That seems like a pretty long time in the age of radio and electronic communications, given all of the "Publicity" was planned months in advance! And the truth is, we don't really know. For some reason it took a very long time for the confirmation of the attack's success to make it to Washington, DC, and set this entire thing into motion. General Groves, the one who received that confirmation and then started up the "Publicity" machine, tried to later figure out why it took so long, but got nowhere with it. I just point it out because it wasn't on purpose, and it does matter a bit — only after the release of this information did the Japanese send a survey team of scientists to Hiroshima to confirm that it was an atomic bomb, and it took them until late August 8th (Tokyo time) to get that confirmation back, and they were to meet on it the next morning (and overnight, the Soviet Union declared war and invaded Manchuria). That means that the Japanese did not really have time to deliberate about Hiroshima (because they hadn't confirmed it was not just misinformation or propaganda) before the Nagasaki bomb was dropped (it happened during their meeting the next morning). I just like to bring this up, because one of the justifications for Nagasaki was "well, they didn't surrender after Hiroshima," but they literally did not have time to confirm what had happened before they were attacked again. And that time delay was not intentional (although the timing of the Nagasaki bombing was not in any way meant coordinated with the Japanese response in mind, either).