Who was President immediately before Harry S. Truman?

Who was First Lady during Franklin D. Roosevelt's presidency? Eleanor Roosevelt was married to which president? Which number president was Harry S. Truman? Who succeeded Harry S. Truman as President of the United States? Which political party did President Harry S. Truman belong to? Which president served from 1945 to 1953? In what year did Harry S. Truman first take office as President? Who served as Vice President under Harry S. Truman?