Book excerpt: It has often been said that we know more about the surface of the Moon than we do about the world's seas and oceans. The study of USOs (Unidentified Submersible Objects) is a case in point. For years, strange phenomena have been reported by people at sea, especially by navies around the globe. Although many of the USO files of the Soviet and Russian Navy remain secret, some have become available due to the painstaking efforts of dedicated researchers. Paul Stonehill and Philip Mantle reveal strange encounters by the Soviet and Russian Navy with things that are not supposed to exist. Here you will read about the mysterious kvakeri, the "swimmers" of Lake Baikal, the oddities of Issyk Kul, inexplicable events within the forbidding Arctic Ocean, and much more. Most of these stories have never been told outside of Russia or the former Soviet Union. They provide yet more evidence that we are not alone. Indeed, they suggest a permanent presence of something unusual in the depths of Earth's large bodies of water.