The 1918 influenza pandemic. The Polio scourge. The AIDS epidemic. The Ebola and Zika outbreaks. Modern history has seen numerous deadly viruses and pandemics that have harmed or killed hundreds of millions of people. And the history is ongoing. The world is facing antibiotic-resistant “superbugs” and infectious diseases tied to climate change, and our previously reliable medicines and treatments no longer always work. What causes these outbreaks, how they spread, and how best to contain and combat them are often open to debate. The most informed opinions from the most respected doctors, researchers, and public health officials are found here, presenting various perspectives on our current and future health and offering both cause for hope and reason to fear.