“Health in All Policies” (HiAP) is the latest manifestation of an ecological approach to public health enhancement — one that recognizes connections between health and other sectors, and that socioeconomic determinants of health are significant. HiAP is related to other holistic, prevention-oriented approaches to collective health, such as the use of Health Impact Assessments to evaluate the health externalities of pending government decisions. Yet HiAP is unique. It goes beyond evaluation of specific projects and policies, and embodies a distinct approach to cross-sectoral public health work.