Part 1 of this study examines the terms which are frequently used in discussions and definitions of health, mental, physical and social. Some of the terms are discarded because of their lack of clarity. A definition of health is presented for consideration. Part 11 discusses health in relation to the family as an ideal and as a social institution. The relationship of the family to the society in which it is located is also considered, and some conclusions are drawn concerning the social conditions which are conducive to health in general and to the health of the family in particular. The suggested definition of health is applied to the family as a social system, in interaction with other social systems. Some implications for research are suggested.