François Duvalier, widely known as 'Papa Doc,' was the 40th President of Haiti, ruling from 1957 until his death in 1971. Initially trained as a physician, he rose to power on a populist and black nationalist platform, later consolidating his authority through constitutional changes that made him President for Life. His regime was characterized by autocracy, corruption, and the use of a brutal secret police force, the Tonton Macoute, to suppress all opposition. Duvalier's oppressive rule left a lasting legacy of political instability and economic stagnation in Haiti, and he was succeeded by his son, Jean-Claude Duvalier.