The first major study of gratitude that shows how "wanting what we have" can measurably change people's lives. Did you know that there is a crucial component of happiness that is often overlooked? Robert Emmons—editor-in-chief of the Journal of Positive Psychology—examines what it means to think and feel gratefully in Thanks! and invites readers to learn how to put this powerful emotion into practice. Scientifically speaking, regular grateful thinking can increase happiness by as much as 25 percent, while keeping a gratitude journal for as little as three weeks results in better sleep and more energy. But there's more than science to embrace here: Emmons also bolsters the case for gratitude by weaving in writings of philosophers, novelists, and theologians that illustrate all the benefits grateful living brings.