Following a frightening meeting with my staff at the peak of the West Africa Ebola crisis, I asked myself, “What would it take to prevent such devastating epidemics?” A new pandemic could kill more than 300 million people worldwide. It could also reduce global GDP by 5 to 10 percent—an impact equivalent to the financial crisis of 2008. There will always be new outbreaks of infectious diseases. But as a medical doctor and a global health leader, I know that by following the prescriptions laid out in this book, it is within the power of modern public-health leaders to keep such outbreaks from exploding into catastrophic epidemics that kill thousands or millions.

I was more alarmed than I had ever been in my 35 years of working in public health. The world was facing a potentially global catastrophe unlike anything I, or any of my colleagues, had ever seen. In response to the fears of my far-flung staff, I knew I had to be straightforward and talk frankly and calmly about the crisis.