While people adept at holding their breath have been exploring the underwater world for a long time, scuba diving is relatively new. In a history of the National Association of Underwater Instructors (NAUI) written by Albert A. Tillman and Thomas T. Tillman, the authors say the first “aqua lung,” was not introduced until 1949. It was developed by Jacques-Yves Cousteau and Emile Gagnon.