Health promotion emerged in the 1990s as a unifying concept which brought together a number of separate, even disparate, fields of study and has become an essential part of the contemporary public health. Regarded by some as the delivery vehicle or mechanism for public health, health promotion now forms an important part of the health services of most industrially developed countries and is the subject of a growing number of professional training courses and academic activities. The implications of this growth have concerned many of those involved in health and health care delivery. Some of the initial momentum for its development sprang from dissatisfaction with what was typified as the bio-medical model of health associated with focus on disease, aetiology, and clinical diagnosis. More recently, health promotion appears to be addressing the mainstream health care issues of the twenty-first century by contributing to newer approaches to health improvement, whole population programmes, health impact assessment, investment for health projects, capacity building, community planning and involvement, and perhaps most importantly, evidence-based practice. Less effort has been made, however, in considering the nature of this new form of knowledge and practice, its salient features and the likely constraints on, and possibilities for, its development. Such reflection continues to be useful for facilitating and development in the field.