Gretchen Rubin, Author of ''The Happiness Project'' & ''Better Thank Before; Mastering the Habits of Our Everyday Lives''

We repeat about 40% of our behaviors every day. Whether they are good or bad Rubin believes when we change our habits, we change our lives. So how do we change? Through research and experimentation, Rubin offers a framework of different strategies to fit our individual personalities. Find out if you are an upholder, questioner, obliger, or rebel. Rubin is the bestselling author of ''The Happiness Project and ''Happier at Home'' with more than two million copies sold worldwide.