Greetings, Teeming Millions:
This is my first post on this BB, so please be gentle.
According to several (not very reliable sources), Harry Truman’s middle name was S (just S). Supposedly, this resulted from some argle-bargle about his parents not being able to decide which uncle to name him after. One of my sources was the Truman Library web site, but there were some weasel words in their account and I’m not quite sure they really endorse that story. Some people even spell his name Harry S Truman.
One clue to his real middle name comes from a scene in a movie whose name is long forgotten. The movie starred George Burns. It was a fantasy movie where an old man and a young man swap bodies (or personalities, depending on how you look at it). The old-man-in-the-young-body finds himself in a history class in college or high school. The instructor gives the no-middle-name legend and the old-man-in-the-young-body enlightens him that Truman’s middle name was actually “Sergey” (a nice Russian name) but Truman wanted to play it down since it was the late Forties and all. So, when asked, Truman would say something like “The S doesn’t stand for anything. It’s just S.” This story has gone on to become “fact”.
Anybody out there got the Straight Dope?
Greetings, ftredeau, and welcome to the SDMB.
Since you are obviously so polite, I’d hate for bad things to happen to you. One way to avoid bad things is to do searches before asking questions. I’m as guilty of violating this suggestion as anyone, so I feel I speak from experience.
I did a quick search on “harry truman middle” with “any date” selected, and found 65 threads, at least one of which was clearly on the same subject as your OP.
Give that a try. Good luck!
ftredeau,
While I did not find as many related threads as alluded to above, I did find this thread that is oddly similar to your question:
http://boards.straightdope.com/sdmb/showthread.php?threadid=10857
The consensus seems to be that it was simply an invention of the movie writers to make the “all-knowing” teacher look like a twit. It does not seem to have any basis in reality. Harry S Truman had been using S as his middle name long before the Cold War.
Reader’s Digest once printed an article about a student who, as an assignment, wrote a report on the former president. The student’s report received some points off because the teacher said the name should be spelled “Harry S. Truman”. The student felt he was in the right and tracked down the former president, and send a letter asking how to spell his name. The letter sent in reply was signed “Harry S Truman”. The student then showed the letter to his teacher; I don’t know if it resulted in a higher grade or not. I’m sure this article is in one of my back issues.
In case anyone’s wondering, that was an actual article written by that same student, not one of the anecdotes.
Nice story, ruined only by the fact that Truman uses the period in the signature. Check it out at http://www.whistlestop.org/study_collections/un/large/un_personnel/un_personnel14-1.htm That signature is typed, so there’s no confusion.
Britannica.com (and the Harry S. Truman library) has this to say: http://www.britannica.com/eb/article?eu=128190
If Truman actual wrote that letter, it was probably just to twit the teacher.
Ah yes, Harry Truman, teacher-twitter par excellance!

Look in any biography of Truuman. I’ve read David McCulloch’s Truman, and there he states that the “S” was chosen so as to offending either side of the family. It could stand for “Ship” or whatever the other family’s name was. McCulloch claims that the custom of using only a middle initial was not uncommon in Missouri at that time.
I’d always been told that there was no period after the “S”. Now I’ve heard from several sources that Truman DID use the period, at least while in office. Is it possible that he started out as “Harry S Truman” but eventually switched to “Harry S. Truman” (possibly because he got tired of explaining it so often)?