This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book outlines the cultural contexts of happiness, discussed in regards to the universality and particularity of the concept. It provides life course theories and research in general and as they pertain to the study of happiness. The book focuses on the physical dimension of well-being, also points to the meta-skills learned by the children, namely that experiences of happiness first and foremost occur within the group. It also focuses on the interpersonal dimension of well-being of Japanese women up to age 50 through the analysis of the marital satisfaction of Japanese housewives in comparison to married, working wives. The book demonstrates that happiness in a Japanese context is largely to be understood as relational and interdependent on the well-being of others. It points the similarities and dissimilarities emerging from the analysis of happiness across the life course in Japan.