Book excerpt: The dramatic story of five key turning points in a thousand years of Western music - discoveries that changed the course of history. Who first invented 'Doh Re Mi...'? What do we mean by "in tune"? Looking back down the corridor of a thousand years, Howard Goodall guides us through the stories of five seismic developments in the history of Western music. His "big bangs" may not be the ones we expect - some are surprising and some are so obvious we overlook them - but all have had an extraordinary impact. Goodall starts with the invention of notation by an 11th-century Italian monk, which removed the creation of music from the hands of the players to the pens of the composers; moves on to the first opera; then to the invention of the piano, and ends with the story of the first recording made in history. Howard Goodall has the gift of making these complicated musical advances both clear and utterly fascinating. Racy and vivid in a narrative full of colourful characters and graphic illustrations of technical processes, he also gives a wonderful sense of the culture of trial and error and competition, be it in 11th-century Italy or 19th-century America, in which all progress takes place. Big Bangs opens a window on the crucial moments in our musical culture - discoveries that made possible everything from Bach to the Beatles - and tells us a riveting story of a millennium of endeavour.