Sail design and sail technology are developing rapidly. Stronger and more stable materials and the increased use of computer-assisted design have benefited both the racing and cruising yachtsman. In this book, the author examines sails, from the basic principles of aerodynamics to the finer points of sail trim. Sailcloth construction, the design and use of headsails, mainsails and spinnakers are explained and illustrated. The author is a racing yachtsman, writer and journalist.