This volume tells the story of Jacques Cousteau, the legendary explorer who discovered the wonders of the underwater world, so close to our lives up to then, and yet so unknown. This exciting epic is narrated by Philippe, Commander Cousteau’s younger son, and in it we will read about his father’s inventions and exciting expeditions aboard the Calypso. We will also learn about the majestic creatures he came to meet in his travels and the dangers these creatures fase on account of the human species’ invasive and destructive habits. The author visited Jan Cousteau, Cousteau's daughter-in-law and widow of his son Philippe, the main character of the book. The author met with her in Washington. Jan excitedly handed over to us for publication the letter she had received from Philippe when he was on an expedition. In addition to Philippe's letter, this title includes a postcard and a second letter simulating Philippe's correspondence with his mother, when he was at boarding school and his parents were travelling around the world on Calypso.