The well-being of the Chinese elderly has recently drawn the attention of a significant number of researchers. This book examines the relationship among personal factors (such as age, sex, income, cognitive functioning, and functional disability), environmental factors (including satisfaction of housing, community, safety, and transportation), person-environment fit, well-being, and the mediating effects of supplementary fit. It represents the first study to integrate the concepts of complementary fit (needs supply) and supplementary fit (value congruence) in one theoretical framework, exploring which of these has a more powerful effect on well-being in later life. Its findings convey noteworthy implications for theoretical, practical, and policy perspectives, and will be of help to those who are interested in person-environment fit theory, as social work and welfare management.