This chapter presents some main interpretations of the concept of health from antiquity until today. There is an emphasis on ideas of health as a positive notion, i.e., as something over and above the absence of disease. After giving a summary of some classic intuitions about health, the chapter concentrates on contemporary attempts to analyze health in terms of well-being and ability. Starting with the famous WHO definition of health, where health is understood as complete physical, mental, social, and spiritual well-being, the chapter turns to a presentation of some scholarly analyses of health, where health is mainly analyzed in ability terms. Examples are taken mainly from the philosophical literature but also from other disciplines. It is noted that almost all definitions in the nursing and feminist literature understand health in positive terms in contrast to such naturalist definitions as present health as merely the absence of disease. The chapter further contains a discussion of health as a culture-dependent notion and makes a comparison between the concepts of human and animal health.