If anyone is truly interested in having more information about the events leading to the use of atomic weapons by the US and of H.S. Truman's role in the decision, I suggest reading the well informed and carefully documented book The Myths of August: A Personal Exploration of Our Tragic Cold War Affair With the Atom by Stewart L. Udall. It's been quite a while since I last read this but as I recall, Truman wasn't told about the bomb or its planned use until just before it was dropped.

      - Mark