James propounded his theories of pragmatism in this book, one of the most important in American philosophy. In a sense, he wished to test competing systems of thought in the "marketplace of actual experience" to determine their validity, i.e. whether adopting a particular philosophical theory or way of looking at the world makes an actual difference in individual conduct or in how we perceive and react to the varieties of experience.

William James (1842-1910), the father of American psychology, the first American philosopher and psychologist, is also an educator and an advocate of pragmatism. One of the founders of the American Functionalist School of Psychology. In 2006, James was named one of the 100 people who influenced the United States by the Atlantic monthly, the leading American journal (No. 62).