Who was President immediately before Richard Nixon?

Who was First Lady during Lyndon B. Johnson's presidency? Lady Bird Johnson was married to which president? Which number president was Richard Nixon? Who succeeded Richard Nixon as President of the United States? Which political party did President Richard Nixon belong to? Which president served from 1969 to 1974? In what year did Richard Nixon first take office as President? Under which president did Spiro Agnew serve as Vice President?