Nathanael G. Herreshoff was the greatest marine designer and builder this country has ever produced. He is credited with the introduction of more new devices in boat design than any other man, and the great yachts that he created for the successful defense of the America's Cup caught the imagination of the entire world. The period of his greatest activity, from 1890 to 1920, is known as "the Herreshoff Era," and his life and career make for a fascinating biography.