Recent research in the cognitive sciences—especially psychology, economics, and neuroscience—has begun to examine the factors that promote personal well-being and happiness. One surprising, but consistent, observation has been that many of the things that are widely believed to be crucial for our happiness—wealth, material possessions, “not missing out”, even good grades—not only fail to make many people happy but can actively undermine the sense of well-being. The course begins by introducing some misconceptions that many people might have about what makes for a satisfying life. We will then examine the psychological biases and other mental quirks of our mind that make it hard for us to identify what actually makes us happy, and we will then discuss what recent research reveals about factors that promote happiness. Importantly, throughout the course, students will be invited to apply these strategies in everyday life. In other words, we will both discuss what new results in cognitive science suggest to anyone interested in better understanding the factors that promote happiness, and also actively put these scientific findings into practice. Along the way, we will review historical and cross-cultural views on the meaning of “happiness”, discuss the limitations of scientific approaches to the topic, and identify aspects of modern life (especially modern life at Harvard) that make it difficult to develop habits that support happiness. Finally, we will also discuss how to apply the new science of happiness beyond our own lives to improve our communities and our planet too.