Gretchen Rubin (www.GretchenRubin.com) is the New York Times Bestselling Author of "The Happiness Project," "Happier at Home" and "Better Than Before." She blogs, pens a monthly newsletter and, with her sister, co-hosts the "Happier with Gretchen Rubin" podcast. In this interview, I dubbed Gretchen the 'Happiness and Good Habits Guru' because her work centers around these topics. Her latest book, "The Four Tendencies," debuts in September.