Introduction

At the beginning of the twenty-first century, key public health issues and challenges have taken centre stage on the global scene. Ranging from arsenic in drinking water to asthma among children and adults; from the re-emergence of cholera and diphtheria, to increasing rates of various forms of cancer; fromHIV andAIDS toMDR-TB, malaria, and hepatitis; from the crises faced by displaced or refugee populations to the new challenges that have emerged for reproductive health and rights; from the experience of public health emergencies as the result of disasters such as tsunamis, earthquakes, and catastrophic storms to the growing spectre of potential global pandemics such as those linked to H5N1. The expansion of serious public health problems, increasingly taking shape on a global scale, has been one of the defining features of recent history.