Earl Nightingale was an American radio speaker and author, dealing mostly with the subjects of human character development, motivation, and meaningful existence. He was the voice during the early 1950s of Sky King, the hero of a radio adventure series, and was a WGN radio program host from 1950 to 1956.
Eckhart Tolle is a spiritual teacher. He is a German-born resident of Canada best known as the author of The Power of Now and A New Earth: Awakening to Your Life's Purpose. In 2008, The New York Times called Tolle "the most popular spiritual author in the United States".