We live in a world that's more interconnected than ever before. Our lives are shaped by outbreaks of disease, of misinformation, even of violence that appear, spread and fade away with bewildering speed. To understand them, we need to learn the hidden laws that govern them. From 'superspreaders' who might spark a pandemic or bring down a financial system to the social dynamics that make loneliness catch on, The Rules of Contagion offers compelling insights into human behaviour and explains how we can get better at predicting what happens next. Along the way, Adam Kucharski explores how innovations spread through friendship networks, what links computer viruses with folk stories and why the most useful predictions aren't necessarily the ones that come true. Now revised and updated with content on Covid-19.