For nearly a century, the name Submarine Signal meant something special to its thousands of employees, to its many competitors, and to practitioners of the art of underwater acoustics the world over. From its modest beginnings in 1901as Submarine Signal Company, through its elevation to a full division of Raytheon Company in 1963, to its submergence into a new organization in 1998, SubSig, as it was known, was a vital part of the free world's defense, an important contributor to underwater acoustics and undersea technology. Though never the subject of an "organizational excellence" survey, it became home and family to the thousands of employees who made SubSig what it was—unassuming yet confident, relaxed yet hard-working, but with an accommodating persistence. History will record that SubSig was a pioneer in sonar and radar technologies. This book is an attempt at describing the events and people that made it a unique place.