In this his forty-somethingth junket into print, Caidin descends from the technology of outer space to the technology of hydrospace, that vast bulk of mystery and water now being penetrated by sonar and other devices. Seldom metaphysical, Caidin never questions the Faustian impasse of modern science, but rather tub-thumps or electronic gadgetry like Teddy Roosevelt for democracy...The importance of the sea, aside from its hideous military uses, is inestimable. Future generations will undoubtedly derive much of the world's protein resources from its fish population. But for present politics, the U.S. today could relieve the globe of its tarvation problem, using fish flours. And the sea bottom, even-more than our land surface, is the great recording house and aquatic library of man's beginnings. Caidin surveys current oceanographic research organizations; international legal problems; bathyscaph activities and lessons learned from submarines in the past. He predicts hesitantly the devices of the future. One of the more amazing of these s a submarine with negative buoyancy (it's built to sink, not float) and with fantastic nuclear power that will push it up 130 m.p.h. Much of this is a fascinating submersion.