This book traces the development of Kepler's ideas along with his unsteady wanderings in a world dominated by religious turmoil. Johannes Kepler, like Galileo, was a supporter of the Copernican heliocentric world model. From an early stage, his principal objective was to discover "e;the world behind the world"e;, i.e. to identify the underlying order and the secrets that make the world function as it does: the hidden world harmony. Kepler was driven both by his religious belief and Greek mysticism, which he found in ancient mathematics. His urge to find a construct encompassing the harmony of every possible aspect of the world - including astronomy, geometry and music - is seen as a manifestation of a deep human desire to bring order to the apparent chaos surrounding our existence. This desire continues to this day as we search for a theory that will finally unify and harmonise the forces of nature.