The author of this book, a young scientist Vladimir Azhazha, is a happy person. He and his comrades had a chance to fulfill what Jules Verne and other science fiction writers only dreamed of - through the windows of a special submarine to look into the secrets of the depths of the sea. In 1957, by decision of the Soviet government, the modern combat submarine was disarmed and converted. Thus was born "Severyanka" - the world's only research underwater laboratory. This exciting book tells about its creation, first voyages, unexpected discoveries and meetings with still unknown inhabitants of the abyss, about the difficult working days of discoverers-submariners, about their friendship and courage.