| Page |
| [2] | U. S. Navy (USN) |
| [3] | University of Pennsylvania Museum—National Geographic Expedition |
| [5] | USN |
| [6] | Woods Hole Oceanographic Institution (WHOI) |
| [7] | Diagram, WHOI; photo, S. Hull |
| [9] | Top, Oregon State University (OSU); bottom, University of California, San Diego, Scripps Institution of Oceanography (SIO) |
| [10] | Lamont Geological Observatory of Columbia University |
| [12] | USN |
| [15] | SIO |
| [19] | R. H. Backus. Physics Today (November 1965), “Sound Reflections In and Under Oceans,” J. B. Hersey |
| [20] | U. S. Bureau of Commercial Fisheries Biological Laboratory, Honolulu, Hawaii |
| [22] | USN |
| [24] | Laboratory of Radiation Biology, University of Washington (LRB) |
| [26] | Jan Hahn |
| [27] | Franklin GNO Corporation |
| [28] | George D. Grice, WHOI |
| [31] | SIO |
| [33] | OSU |
| [35] | Monsanto Research Corporation |
| [37] | USN |
| [38] | Lane-Wells Company |
| [39] | Research Triangle Institute |
| [43] | USN |
| [46], [47] & [48] | Martin-Marietta Company |
| [49] | The Photo Mart |
| [53] | Top, Metropolitan Water District of Southern California; bottom, Bechtel Corporation |
| [55] | U. S. Bureau of Commercial Fisheries, Fish and Wildlife Service; inset, Brookhaven National Laboratory |
| [56] | Norsk Folkemuseum, Oslo, Norway, courtesy The Mariners Museum, Newport News, Virginia |
| [57] | National Science Foundation |
| [61] | S. Hull |
| [Cover photo] courtesy James Butler, USN |
| [Author’s photo] courtesy General Dynamics Corporation |
| [Frontispiece] from Jan Hahn |