We live in an era in which public health is debated all around us, every day. Big questions emerge constantly: What’s the best way to deliver health care or respond to natural disaster? How will climate change affect health? What can we do to ensure clean, safe water for a planet of seven billion? Some of the puzzles that we in public health try to solve are fairly recent, such as the obesity and diabetes epidemics. Other quandaries have been around longer. The HIV/AIDS epidemic is three decades old now. Cigarettes have been identified as killers for more than half a century. Malaria has been with us.
