A passionate proponent of living simply and in harmony with nature, Thoreau is remembered today as a pillar of the modern conservation movement.

Was Thomas Aquinas a theologian or a philosopher? By most accounts he was both, and his blending of the two disciplines resulted in a new approach to the Bible and its teachings.

The 16^th president of the United States was one of the nation’s most illustrious, respected and steadfast leaders. Yet in key areas, his views evolved greatly over the course of his life.

Martin Luther King Jr. was not the leader of the civil rights movement, but his voice resonated with a wide variety of listeners, introducing them to the reality of a national injustice. Who was this man, and how did he become such an icon?

Ronald Reagan had a vision of a world safe from the threat of nuclear Armageddon.

Henry Ford will always be remembered for revolutionizing factory work and, of course, for giving the world the Model T.

Today’s debate between methods of attaining knowledge—one divinely revealed, the other gained by rational inquiry—is a significant aspect of Aristotle’s legacy.

Jacques Cousteau was willing to go to whatever lengths were necessary to protect the seas.

Carl Gustav Jung founded an approach he named Analytical Psychology, many tenets of which have led some to refer to him as a “founding father of the New Age.”

Little Manya Sklodowski (Marie Curie) became the first woman to earn the Nobel Prize in Physics, and the first person ever to earn a second Prize.