Book excerpt: 'Witty, knowledgeable and mind-expanding' RICHARD FISHER | 'A joyful romp' TOM HARFORD | 'A fun and inspiring teaser for curious minds' JÉRÉMIE HARRIS Every so often, a new idea comes along that changes everything. Vaccinations. Relativity. Fascism. Can we imagine a world before the invention of writing? What would Christianity have looked like without with a concept of hell? Sometimes these ideas come along suddenly: Copernicus suggesting the earth revolves around the sun; Gutenberg's printing press, Darwin's theory of evolution. Sometimes they evolve over generations: the institution of marriage; the development of animal husbandry; the understanding of genetics. Either way, once the idea gains a foothold, nothing is the same again. This fascinating little book tells the stories behind 150 revolutionary concepts and explains why they are important. Taken from the realms of science, politics, society, religion and technology, these are the big ideas that have changed the world - in a nutshell.