The worst chemical disaster ever could be happening right now. In India and Bangladesh between forty and eighty million people are at risk of consuming too much arsenic from well water that might have already caused one hundred thousand cancer cases and thousands of deaths. Many millions elsewhere in South-East Asia and South America may soon suffer a similar fate. Venomous Earth is the story of this tragedy: the geology, the biology, the politics and the history. It starts in Ancient Greece, touches down in today's North America and takes in William Morris, alchemy, farming, medicine, mining and a cosmetic that killed two popes.