Harry S. Truman was an American politician who served as the 33rd president of the United States from 1945 to 1953.

Truman actually had no middle name. His parents gave him the middle initial S to honor both of his grandfathers: Anderson Shipp Truman and Solomon Young. Since the S did not stand for anything, Truman didn't use a period after it for most of his life. After he was elected president, the editors of the Chicago Style Manual informed Truman that omitting a period after his middle initial was improper grammar and a bad example for America's youth. From that moment on, the 33rd President signed his name Harry S. Truman or put all the letters in his name together as in HarrySTruman.

Truman enlisted in the Missouri National Guard in 1905, and served until 1911 in the Kansas City-based Battery B, 2nd Missouri Field Artillery Regiment, in which he attained the rank of corporal. When the United States entered World War I, Truman rejoined Battery B, successfully recruiting new soldiers for the expanding unit, for which he was elected as their first lieutenant.

In July 1918, Truman became commander of the newly arrived Battery D, 129th Field Artillery, 35th Division. It was known for its discipline problems, and Truman was initially unpopular because of his efforts to restore order. Despite attempts by the men to intimidate him into quitting, Truman succeeded by making his corporals and sergeants accountable for discipline. He promised to back them up if they performed capably, and reduce them to private and return them to the ranks if they did not. Battery D did not lose any men while under Truman's command. To show their appreciation of his leadership, his men presented him with a large loving cup upon their return to the United States after the war.

Although he briefly attended Spalding's Commercial College and took night classes at the Kansas City Law School, Truman is the only president since William McKinley (elected in 1896) who did not earn a college degree.

As a U.S. Senator from Missouri, Truman served on the high-profile Appropriations and Interstate Commerce Committees, but he was largely ignored by Democratic President Franklin D. Roosevelt and had trouble getting calls returned from the White House.

Truman served as vice president during Franklin D. Roosevelt's unprecedented fourth term of office and succeeded to the presidency upon Roosevelt's death.

In August 1945, the Japanese government refused surrender demands as specifically outlined in the Potsdam Declaration. With the invasion of mainland Japan imminent, Truman approved the schedule for dropping the two available bombs. Truman always said attacking Japan with atomic bombs saved many lives on both sides. Military estimates for the invasion of mainland Japan were that it could take a year and result in 250,000 to 500,000 U.S. casualties. Hiroshima was bombed on August 6, and Nagasaki three days later, leaving 105,000 dead. Japan agreed to surrender the following day.

The Marshall Plan was an American initiative passed in 1948 that transferred over $12 billion (equivalent to over $129 billion as of 2020) in economic recovery programs to Western Europe after the end of the war. The goals of the United States were to rebuild war-torn regions, remove trade barriers, modernize industry, improve European prosperity, and prevent the spread of Communism.

The Fair Deal offered new proposals to continue New Deal liberalism, but with the Conservative Coalition controlling Congress, only a few of its initiatives became law and then only if they had considerable GOP support. The most important proposals--aid to education, universal health insurance, the Fair Employment Practices Commission, and repeal of the Taft-Hartley Act--were all debated at length, then voted down.