In 1930, Cousteau was admitted to the École Navale (Naval Academy) in Brest and became a gunnery officer of the French Navy, which gave him the opportunity to make his first underwater experiments. He was training to become a pilot, but a serious car accident ended his aviation career. In 1936 Jacques- Yves Cousteau tested a model of underwater goggles, perhaps the ancestors of modern diving masks.

In 1937 he married Simone Melchior. He took part in World War II, and during the conflict he found the time to be co-inventor, with Emile Gagnan, of the first commercially successful open circuit type of Scuba diving equipment, the aqua-lung in 1943. Among the things that prompted him to develop efficient air-breathing free-swimming diving gear, were two oxygen toxicity accidents that he had earlier with rebreathers.

After WWII, while still a naval officer, he developed techniques (including forming an unofficial clearance diver unit using his taccos) for minesweeping of France's harbors. He also explored shipwrecks.

In August of 1956, Cousteau and fellow diver Frederic Dumas explored one of the deepest known underground rivers, the Sorgue, at Fontaine-de-Vaucluse in Provence, France. During this expedition both divers nearly died as carbon-monoxide had accidentally been sucked into their air intake from a diesel-powered air compressor used to fill their aqua-lung, which they had recently pioneered. When the divers became lethargic and disoriented at a depth of 150 feet (46 meters) below surface, both divers helped each other get back to the mouth of the cave. Ironically, another set of divers immediately entered the water after Cousteau and Dumas had been rescued, nearly succumbing to the same problem. Cousteau would return with his crew to Fontaine-de-Vaucluse in 1967 and his robotic Télénaute, a remote-control mini submarine guided by a tethered cord, to continue the quest to find the origin of the river. Cousteau guided the Télénaute to a depth of 347 feet (106 meters) before reaching an impass.

Subsequently, Cousteau made an underwater film called Épaves (Shipwrecks). While planning to make it, he found that under postwar shortages, unexposed movie film was impossible to buy, so his wife had to make movie reels by gluing together end-to-end dozens of small short unexposed film reels intended for children's toy cameras. Showing this film proved vital in persuading the French Navy to make official his unofficial diving capsule.

In 1950, shortly after Cousteau's 40th birthday, Loel Guinness (who was named the president of the French Oceanographic Campaigns) bought the ex-Royal Navy minesweeper Calypso when it was doing service as a ferry between Malta and Gozo. Guinness leased it to Cousteau for a symbolic one franc a year.

In the Calypso Cousteau visited the most interesting waters of the planet, including some rivers. During these trips he produced many books and films. Cousteau won three Oscars for The Silent World (1956), The Golden Fish, and World Without Sun (1964), as well as many other top awards including the Palme d'Or in 1956 at the Cannes Film Festival. His work did a great deal to popularize knowledge of underwater biology and was featured in the long-lived documentary television series The Undersea World of Jacques Cousteau which began in 1966.

In the mid-1950s, Cousteau had worked with Luis Marden aboard the Calypso, in which they pioneered new techniques in underwater photography. In 1963, along with Jean de Wouters, Cousteau developed the underwater camera named "Calypso-Phot" which was later licensed to Nikon and became the "Calypso-Nikkor" and then the Nikonos. Together with Jean Mollard, he created the SP-350, a two-man submarine that could reach a depth of 350 m below the ocean's surface. The successful experiment was soon repeated in 1965 with two submarines that reached 500 m depth.

In 1957, Cousteau was made director of the Oceanographic Museum in Monaco, created the Underseas Research Group in Toulon, was the leader of the Conshelf Saturation Dive Program (long-term immersion experiments, the first manned undersea colonies) and was one of the few foreigners who has been admitted to the American Academy of Sciences. The Calypso was later sunk in a Singapore harbor, when it collided with a barge. It was later refloated and moved to France, where there are hopes of restoring it.

Cousteau's popularity was decreasing. In October 1960, a large amount of radioactive waste was going to be discarded in the sea by the European Atomic Energy Community. Cousteau organized a publicity campaign which gained wide popular support. The train carrying the waste was stopped by women and children sitting on the railway, and it was sent back to its origin. The risk was avoided. During this, a French government man had said falsely to a newspaper that Cousteau had approved the dump; Cousteau managed to get the newspaper to issue a correction. In November 1960 in Monaco, an official visit by the French president Charles de Gaulle turned into a debate on the events of October 1960 and on nuclear experiments in general. The French ambassador already had suggested that Prince Rainier avoid the subject, but the president allegedly asked Cousteau in a friendly manner to be kind toward nuclear researchers, to which Cousteau allegedly replied: "No sir, it is your researchers that ought to be kind toward us."

In 1973, along with his two sons, and Frederick Hyman who was the first President, he created the Cousteau Society for the protection of ocean life; it now has more than 300,000 members.

In 1977, together with Peter Scott, he received the UN international environment prize.

In 1985 he received the Presidential Medal of Freedom from Ronald Reagan.

In 1992 he was invited to Rio de Janeiro, Brazil, for the United Nations' international conference on environment and development, and then he became a regular consultant for the UN and the World Bank.

source: en.wikipedia.org