Understanding how Covid-19 started is more important than we know for the future of humankind. Determining whether the virus came from nature or from a lab will help us to safeguard against the next pandemic.This disease will forever punctuate modern history. It has led to the deaths of millions, sickened hundreds of millions and affected the lives of almost every person on the planet. We now know that Covid is here to stay.Genetic engineering expert Dr Alina Chan and renowned science writer Matt Ridley examine the origins of SARS-CoV-2, the virus responsible for Covid-19, using their formidable skills to scrutinise arguments and rigorously analyse the sprawling data. Viral is a fascinating account that takes in pangolins, horseshoe bats, internet sleuths and misleading scientific papers. It details the evidence and investigates hypotheses for the virus origin, chief among them a potential laboratory leak or a natural spillover.Science has made great strides over the last decades. Chan and Ridley give an insight into the proliferating pathogen research and virus hunting around the world. Whatever the source of the virus, the world needs to adopt new policies and strategies to prevent or mitigate future outbreaks.Set in the caves and mineshafts, food markets and wildlife smugglers' stores, laboratories and databases of China and elsewhere, Viral is a page-turner that reads like a detective novel and goes deeper into the deepest mystery of the day than any other work.This is the book on the search for the origin of Covid-19.