EDITORIALThe concept of illness behaviour: culture, situation and personal predisposition 1 The concept of illness or disease refers to limited scientific models for characterizing constellations of symptoms and the conditions underlying them. The concept of illness behaviour, in contrast, describes the ways in which people respond to bodily indications and the conditions under which they come to view them as abnormal. Illness behaviour thus involves the manner in which individuals monitor their bodies, define and interpret their symptoms, take remedial action, and utilize sources of help as well as the more formal health care system. It also is concerned with how people monitor and respond to symptoms and symptom change over the course of an illness and how this affects behaviour, remedial actions taken, and response to treatment. The different perceptions, evaluations and responses to illness have, at times, a dramatic impact on the extent to which symptoms interfere with usual life routines, chronicity, attainment of appropriate care and cooperation of the patient in treatment. Variables affecting illness behaviour usually come into play well before any medical scrutiny and treatment .A crucial premise in the study of illness behaviour is that illness, as well as illness experience, is shaped by sociocultural and social-psychological factors, irrespective of their genetic, physiological or other biological bases. Away from the research laboratory, illness is often used to achieve a variety of social and personal objectives having little to do with biological systems or the pathogenesis of disease. The boundaries of illness and its definitions are potentially very broad, and the illness process can be used to negotiate a range of cultural, social and personal tensions in the home, at work, and in the community at large.Cultural definitions, social development and personal needs shape the experience of illness and meanings attributed to physical factors that serve as its basis. While the magnitude, severity, persistence and character of symptoms affect and establish limits for personal and social definitions, there is considerable variability in what is perceived, how it is defined, the interventions that are considered and used, requests for support and special consideration, and illness outcomes.A major gap in our knowledge concerns those processes that lead persons exposed to similar stressors to respond differentially at a physical, psychological or social level. While the neuropsychological bases of alternative patterns of expressing distress remain uncertain, many research workers have ingeniously demonstrated that there may be conversions among different levels of experience and that substitutability among levels of response is to some unknown degree operative (Graham, 1972).