Eighteen-year-old chemistry student William Perkin's experiment has gone horribly wrong. But the deep brown sludge his botched project has produced has an unexpected power: the power to dye everything it touches a brilliant purple. Perkin has discovered mauve, the world's first synthetic dye, bridging a gap between pure chemistry and industry which will change the world forever. From the fetching ribbons soon tying back the hair on every fashionable head in London, to the laboratories in which scientists first scrutinized the human chromosome under the microscope, leading all the way to the development of modern vaccines against cancer and malaria, Simon Garfield's landmark work swirls together science and social history to tell the story of how one colour became a sensation.