The CoV-19 epidemic is set to be the most significant health emergency of our time. In concise, immediate prose, Italian physicist and novelist Paolo Giordano explains how disease spreads in our interconnected world: why it matters, how it impacts us, how we must react. Writing from his home in Rome as Italy implements the largest peace-time lockdown ever recorded in a democratic country, Giordano expands his focus to other forms of contagion linked to this epidemic – fake news, the environmental crisis, nationalism and xenophobia, our lack of imagination in promoting a new kind of global community.