If you've ever dreamed of viewing the wonders of the ocean floor, here's an eyewitness account. Van Dover (Oceanography/Univ. of Alaska, Fairbanks), a contributor to Discover and Smithsonian magazines, was the first woman to qualify as a pilot of Alvin, a tiny research vessel capable of taking its pilot and two scientists to depths of nearly three miles below the surface of the ocean, the least-known habitat for living forms on our planet. Having worked as a technician on oceanographic expeditions before enlisting in a Ph.D. program, Van Dover went against all advice to enter the submersible pilot training program so as to see firsthand the strange and often beautiful life forms that populate the area near the hydrothermal vents--undersea geysers spouting superheated water (over 600 degrees Fahrenheit). Many of these organisms have been discovered only in the last decade or so: six-foot-long crimson tubeworms, eyeless shrimp, and strangely shaped crabs. They inhabit an environment of frightening extremes--crushing water pressure, almost total darkness, and frequent volcanic eruptions. Yet even here, the polluting by-products of civilization are beginning to appear: At the very bottom of the sea a layer of beer cans and plastic trash bags is slowly accumulating. It would be ironic if this exotic environment, so recently discovered, were destroyed before it could be fairly explored. Van Dover's experience as a submersible pilot allows her access to an invaluable body of material from a cutting-edge science. At the same time, she is adept at giving her narrative a human dimension, whether talking about her childhood as a mechanic's daughter or about daily life aboard the cramped ship that is home to Alvin's crew when they are not exploring the depths. A simply told but richly evocative scientific memoir by one of the pioneers of the last frontier on Earth.