"We have tried to find the entrance to the great hydrosphere because we feel that the sea age is soon to come."

So Captain Jacques-Yves Cousteau, a French navy gunnery officer, sums up his motives for devoting fifteen years to pioneering undersea explorations, in the course of which he has made more than 5,000 dives. Cousteau's work is an important milestone on the road of man's return to the sea. The era of the "menfish" began when he, along with Philippe Taillez, another naval officer, and Frédéric Dumas, an experienced civilian diver, made successful descents with the first aqualung a decade ago.

Aqualung equipment consists of one to three tanks of compressed air strapped on the diver's back, a face mask, and a mouth piece through which the diver inhales air from his tanks and exhales. He is completely self-contained….

"The Silent World" is a fascinating book, the distillation of Cousteau's experience undersea. After the war he and his associates salvaged torpedoed vessels and the scuttled French fleet, swimming freely through the rigging encrusted with barnacles, weed-hung and ghostly; they swam down shadowy gangways, passing from deck to deck and exploring drowned cabins and engine rooms. Turned archaeologists, the aqualungers found the remains of an argosy presumably sunk about 80 B.C. while en route from Athens to Rome with loot that included Ionic columns, marble statuary, and bronze figures. The divers filmed fishermen's trawl nets as they lumbered along the ocean floor, sending up fishes like frightened rabbits. They followed a submarine laying mines and photographed men emerging from the escape hatch.

Captain Cousteau succeeds admirably in giving his readers a sense of personal participation in these explorations of a strange world. We feel that we know what a diver sees, feels, and thinks as he descends into the blue twilight of the sea.

Through the diver's mask, objects seem larger and nearer than they are. Tropical reefs are a fairyland riot of color down to perhaps twenty-five feet; below that level, colors rapidly fade into a twilight blue. At fifty feet, red becomes black and orange disappears. Down 120 feet, the blood of a man or a fish runs green. Deeper, only ultraviolet is left. But even in the "blue zone" the colors are there, if unseen. When the divers took down powerful electric lights, they were dazzled by a "harlequinade of color dominated by sensational reds and oranges, as opulent as a Matisse."…

For many years that veteran of countless helmet dives, William Beebe, has been telling us that the so-called "monsters of the deep" are monsters only in the imagination of writers who are over-imaginative and under-experienced. Capt. Cousteau convincingly seconds Dr. Beebe. The octopus, the manta ray, the moray eel—alarming as their appearance may be—are creatures who wish only be be allowed to go about their normal occupations, and these definitely do not include molesting human divers. Only on sharks does Capt. Cousteau reserve judgment, having found their behavior unpredictable. A twenty-five-foot "man-eater" fled in seeming alarm at the sight of divers. The quite different story of an encounter with a much smaller shark is too thrilling and full of suspense to spoil by telling it here.

One could go on indefinitely about the carnival behavior of fish during a rainstorm, about the eerie quality of the undersea world at night, about the octopus "city" where each of these extraordinary mollusks occupied a "house" roofed with a flat stone propped up, like a lean-to, with other stones. This is a book that leads us on, page by page, and when the end is reached we are very likely to begin again at Page 1.

And beyond its ability to stir our imaginations and hold us fascinated, this is an important book. As Capt. Cousteau points out, in the future we must look to the sea, more and more, for food, minerals, petroleum. The aqualung is one vital step in the development of means to explore and utilize the sea's resources.

Rachel L. Carson, "The Strange, Dramatic Sea-Depths Where Man Can Now Venture," in New York Herald Tribune Book Review, February 8, 1953, p. 3.