Harry S. Truman (1884-1972) was the 33rd President of the United States, serving from 1945 to 1953 after assuming office upon the death of Franklin D. Roosevelt as the 34th vice president. A Democrat from Missouri, Truman implemented key post-World War II policies including the Marshall Plan to rebuild Western Europe, the Truman Doctrine, and the establishment of NATO to counter Soviet expansion. He proposed liberal domestic reforms continuing the New Deal coalition but faced resistance from a conservative Congress. Truman authorized the atomic bombings of Hiroshima and Nagasaki, ending WWII, and later navigated the onset of the Cold War, the Korean War, and early civil rights advancements.

Born in Lamar, Missouri, Truman was raised in Independence, working various jobs including farming, banking, and oil drilling after high school graduation in 1901, as poor eyesight prevented West Point attendance. He served as a captain in World War I, gaining leadership experience that propelled his political career. After a failed haberdashery business in the 1920s recession, he entered politics backed by Kansas City Democratic boss Thomas Pendergast, becoming a county judge in 1922, later presiding judge, U.S. Senator in 1934, and vice president in 1944.

Historians rank Truman among the nation's better presidents for his decisive leadership, economic transition from wartime to peacetime, and protection of New Deal reforms. He was known for his folksy style, diarist habit, and nickname 'Give 'em Hell Harry.'