COVID-19 is caused by a virus. The COVID-19 pandemic is caused by a lack of good information. A pandemic is essentially an information problem: this is the enlightening and provocative idea at the heart of this book. If we solve the information problem, argues economist Joshua Gans, we can defeat the virus. For example, when we don’t know who is infected, we have to act as if everyone is infected. If we actively manage the information problem–if we know who is infected and with whom they had contact–we can suppress the virus or buy time for vaccine development.