Science began with the Greeks. Medicine, Anatomy, Astronomy, Mathematics and Cosmology were all invented in their world. Plato, Aristotle, Pythagoras, Archimedes and Hippocrates were amongst its stars, master architects all of the modern as well as the ancient. Today science is a familiar language, and commands authority. But it is remarkable that humans ever developed a 'scientific' attitude to the natural world - it happened only once and it happened in Greece. The Greeks' predecessors observed the heavens, but deduced little in the way of theory. Their description of the world used poetry and mythology; disease, for example, was punishment from the gods and the cure was piety. For Hippocrates and his followers, by contrast, disease had physical causes and was treatable by physical means. The notion of the atom - cornerstone of contemporary physics - was a Greek one. Andrew Gregory unravels the genesis of science in this fascinating exploration of the origins of Western civilisation, and our desire for a rational, legitimating system of the world.