Harry S Truman was President of the United States from 1945 to 1953. He dropped the "bomb" on Japan. History records this man as humble, and his Presidency is plagued because of the Korean Conflict. History judges him favorably but his decision to drop the "bomb" is however called into question. We know the terrible suffering that happened in Hiroshima and Nagasaki and historians blame Truman for that. We can only guess what suffering might have happened if Japan hadn’t surrendered and had carried on with a Suicidal war.
Truman is more positively remembered ending military segregation. Unfortunately, his other Civil rights policies were blocked by Congress. Truman served in World War I in France, ended World War II and Stalin began the Cold War soon after. FDR only met with Truman twice during Truman's time as Vice President (82 days). When he assumed the presidency following FDR's death, Truman wasn't even aware of the Manhattan Project.
Truman is the only president to only have a letter for his middle name.