Chapters 11 to 13 continue the general theme of the previous two: A person’s happiness or unhappiness is a function of himself or herself as well as of inputs from the environment. As in chapter 10, four questions are addressed. Is the personal feature under consideration linked to differences in people’s conception of the nature of happiness? Is that personal feature associated with differences in levels of happiness? Are different kinds of individuals exposed to different inputs from the environment, with possible varying impacts on happiness? Is the strength of the association between job characteristics and happiness influenced by the personal attribute under investigation? The first three issues are examined in the present chapter, and chapter 12 considers the fourth possibility. Some of these themes are carried forward into chapter 13, which reviews a range of perspectives on person-environment fit, and further explores personal salience and occupational values.