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 uniquely insightful book, a scientist and a writer join forces to try 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 kilometres 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 travellers to the city, no smouldering epidemic in a rural area, no rapid adaptation of the virus to its new host—human...