Twenty-four centuries have passed since the doctrine of AirsWaters Places was articulated in the Hippocratic corpus, promoting a mutually constitutive vision of humankind and climate. Yet the "airs, waters, places tradition" has proved remarkably resilient and adaptable as a framing device for relations among nations, natural and human resources, and human health. Redeployed in diverse historical contexts across time, the relationship between climate and humans has evolved from a dependent one in which human constitution and health are determined by climate to an interdependent one in which humans and climate influence one another. Recent scholarship extends the ways in which historians of colonial medicine, neo-Hippocratic medicine, public health, tropical disease, and race have characterized the climate-human nexus and its attendant politics. Through the exploration of the works of circumnavigators, physicians, physiologists, ecologists, geographers, paleoanthropologists, and economists, contributors to this special issue offer some new and sometimes challenging interpretations of medical climatology: beyond the link between tropical medicine and colonialism, beyond temperate versus tropical, beyond latitude to think of altitude.