Buddy diving just before and after the Second World War. After the invention of the "aqualung" by Cousteau and Gagnan, the first commercially underwater breathing apparatus became available for sale for sporting purposes in the late 1940s. As the new sport of scuba diving rapidly expanded through the 1950s, several sporting organisations—notably the YMCA—began programmes to train swimming enthusiasts in this new aquatic pastime, and began to codify what they believed were proper practises for this expanding sport. The YMCA considered the buddy system a useful corollary to the "never swim alone" rule of their swimming and lifesaving programmes. Cousteau himself independently
Jacques Cousteau with American television companies (ABC, Métromédia, NBC) created the series "The Undersea World of Jacques Cousteau", with the character of the commander in the red bonnet inherited from standard diving dress intended to give the films a "personalized adventure" style. This documentary television series ran for ten years from 1966 to 1976. A second documentary series, "The Cousteau Odyssey", ran from 1977 to 1982 on public television stations. In 1970, he wrote the book "The Shark: Splendid Savage of the Sea" with his son Philippe. In this book, Cousteau described the oceanic whitetip shark as "the most dangerous of all