Looking back over more than 30 years working in public health globally and in the United States, I can't recall a year with as pronounced a divergence: big advances and big setbacks. Heart health improved in parts of the world, but in the US, the decline in cardiovascular deaths stalled, contributing to a shocking decline in life expectancy. We know more about epidemic preparedness than ever, but preventable infectious disease outbreaks continue. More countries are reducing smoking, but e-cigarettes are hooking a new generation of kids into lifelong nicotine addiction. [...]