Commemorating the 400th anniversary of Galileo's historic first recorded astronomical observations and to coincide with the United Nations International Year of Astronomy 2009, this book tells the epic story of the historical development of astronomy which caused a revolutionary change in human outlook, in its impact upon both scientific thinking and religious belief. It is a fascinating story, well researched and told in a scholarly yet exciting narrative that will be read with enjoyment and profit by astronomers, historians and the general public. Formerly titled The Great Astronomical Revolution, the book includes a new foreword, new illustrations and colour plates.