The power of positive thinking. It is an idea deeply rooted in American culture, from Oprah to The Secret to the mass-media ministries of Joel Osteen and T.D. Jakes. Yet no one has examined how this one simple idea—to think positively—has morphed from metaphysics into mass belief.

In One Simple Idea, Mitch Horowitz tracks the history of the positive-thinking movement from its pioneers to its most dramatic personalities, including Dale Carnegie and Norman Vincent Peale. Positive thinking has been the root of studies on the placebo effect, the 12-step approach to overcoming addition, and the mind-body connection in treating illness. And it is central to the American idea of success, as seen in political messages like Ronald Reagan’s “Nothing is impossible” or President Obama’s “Yes, we can” and slogans such as the U.S. Army’s “Be all you can be” and Nike’s “Just do it.”

This paperback edition includes new exercises and methods, which readers can use to test the validity of positive-mind mechanics in their daily lives. One Simple Idea answers the age-old question—Does it work?—and shows that, yes, positive thinking can change the world.