We often think of health as a self-centric phenomenon that begins and ends with "me", but as we'll explore throughout this series our personal health is just one plot line in a rich story of evolving research and policies that make up the world of public health. So what is public health anyway? Well, public health is an approach to preventing disease, prolonging life, and promoting health for literally everyone. It is a money-saving, life-extending, world-bettering cheat code for improving the world, so we'll spend the rest of this series examining how and where it is working, where it isn't working, and how so much of our health is influenced by the world around us.