Decisive, blunt, fair-minded, and well-informed, Harry S. Truman was the "common man" president. He had worked as a farmer, a clerk, and a salesman, among other jobs; he served his country during World War I (1914-18); and he became a straight-talking and honest politician who continually beat the odds to win elections.

As president, Truman had to face some of the most profound issues of the twentieth century. He was the first leader to authorize the use of nuclear weapons—the atomic bomb. He supported war crimes trials against Nazi leaders following World War II (1939-45). (Nazi is the term commonly used to refer to members of the National Socialist Party of Germany.) Truman fought aggressively through diplomatic and military means to check the spread of communism (theory that holds that private property should be banned and that goods should be made available...