Robert Emmons, PhD, is a Professor of Psychology and Lab Director of the Emmons Lab at University of California, Davis. He is the world's leading scientific expert on gratitude and the founding editor-in-chief of The Journal of Positive Psychology. He is a prominent speaker and the author of numerous books, including Gratitude Works!: A 21-Day Program for Creating Emotional Prosperity (Jossey Bass, 2013) and Thanks! How the New Science of Gratitude Can Make You Happier (Houghton Mifflin, 2008), The Psychology of Ultimate Concerns: Motivation and Spirituality in Personality (Guilford Press, 2003), The Psychology of Gratitude (OUP USA, 2004) and Words of Gratitude for Mind, Body and Soul (with Joanna Hill, Templeton Foundation Press, 2002) in addition to hundreds of articles.