Positive psychology is the scientific study of optimal human functioning. Happiness is not the same as optimal functioning but is a closely related phenomenon. Happiness is a major manifestation of optimal functioning, since we are hard-wired to feel good when functioning well. Happiness is also a determinant of optimal functioning, since happiness "broadens" our behavioral repertoire and "builds" resources. Consequently, happiness is a major topic in positive psychology. This chapter first deals with the question as to whether greater happiness is possible, and does so by taking stock of the available evidence. It then addresses the question of how happiness can be furthered, and this requires a look ahead.