Jonathan David Haidt is an American social psychologist and author.

Miguel Ángel Ruiz Macías, better known as Don Miguel Ruiz, is a Mexican author of Toltec spiritual and personal development texts..

Stephen Richards Covey was an American educator, author, businessman, and speaker.

French aristocrat and political thinker Alexis Charles Henri de Tocqueville transformed how the world understood democracy through his keen observations of 19th-century America.

Friedrich Wilhelm Nietzsche was a German philosopher and writer who started his career as a classical philologist and turned to philosophy early in his academic career.