Social justice is the foundation of public health. This powerful proposition-still contested-first emerged around 150 years ago during the formative years of public health as both a modem movement and a profession. It is an assertion that reminds us that public health is indeed a public matter, that societal pattems of disease and death, of health and well-being, of bodily integrity and disintegration, intimately reflect the workings of the body politic for good and for ill. It is a statement that asks us, pointedly, to remember that worldwide dramatic declines-and continued inequalities-in mortality and morbidity signal as much the victories and defeats of social movements to create a just, fair, caring, and inclusive world as they do the achievements and unresolved challenges of scientific research and technology. To declare that social justice is the foundation of public health is to call upon and nurture that invincible human spirit that led so many of us to enter the field of public health in the first place: a spirit that has a compelling desire to make the world a better place, free of misery, inequity, and preventable suffering, a world in which we all can live, love, work, play, ail, and die with our dignity intact and our humanity cherished.