This book will discuss the topic of sailing on the solar wind, the continuous outpouring of photons from the Sun. When these photons reflects off the sail, they give a “push” to it, exchange a small amount of momentum. In the vacuum of space, this builds up fairly quickly. As the bombardment is continuous, the velocity keeps building up as well. A solar powered craft can be steered by changing the angle of the sail to the particle stream. It can be used to fly toward the Sun by tacking, a zig-zag maneuver commonly used by sailboats. At least, solar sailing ships won't need to worry about salt water corrosion, and wet sails. But we do have to worry about “weathering” of the solar sails due to the constant flux.