A new virus descended on the human species in 2019 wreaking unprecedented havoc. Finding out where it came from and how it first jumped into people is an urgent priority, but early expectations that this would prove an easy question to answer have been dashed. Nearly two years into the pandemic, the crucial mystery of the origin of SARS-CoV-2 is not only unresolved but has deepened.

In this conversation based on the uniquely insightful book, Viral: The Search for the Origin of COVID-19, Matt Ridley reviews how he and his co-author Alina Chan have tried to get to the bottom of how a virus whose closest relations live in bats in subtropical southern China somehow managed to begin spreading among people more than 1,500 kilometers away in the city of Wuhan. They grapple with the baffling fact that the virus left none of the expected traces that such outbreaks usually create: no infected market animals or wildlife, no chains of early cases in travelers to the city, no smoldering epidemic in a rural area, no rapid adaptation of the virus to its new host — human beings.

To try to solve this pressing mystery, Ridley delves deep into the events of 2019 leading up to 2021, the details of what went on in animal markets and virology laboratories, the records and data hidden from sight within archived Chinese theses and websites, and the clues that can be coaxed from the very text of the virus’s own genetic code.