Guide to Happiness. Our sense of happiness is influenced 50 percent by our basic attitude, 10 percent by life circumstances, and an astonishing 40 percent by our own active influence. This insight comes from the renowned American psychologist Sonja Lyubomirsky in her freshly revised standard work. At the center is a scientifically based model that helps us create our own happiness strategy from twelve happiness activities. Happiness has nothing to do with believing in gurus or reading calendar quotes. Rather, we can rely on scientific facts to give happiness a boost! "If you are looking for a scientifically grounded guide on how to lead a happier life, then this is the perfect book for you." Martin Seligman, author of "Flourish.".