With this book that you are holding in your hands you are embarking on an adventure... ...like when you throw a paddle into a calm lake and it begins to create circular ripples that spread out... ...like when a beam of light passes through a prism and is dispersed into the colors of its spectrum... ...like when you follow the thread of Ariadne... ...like the question in zen philosophy of whether the bridge is moving or the river... ...simple, isn''t it? When you are in a dark room, you learn to make a simple move: to press the switch and turn on the light.