In an introductory chapter (1) the author presents a general view of the remarkable evolution of the remote sensing technique during the last decades, all of great importance for operations in more or less ice-covered sea areas, especially at the exploration of natural resources, such as oil, gas and minerals, and at surface shipping as well as under-ice navigation. In all cases the best possible position-fixing and a true knowledge of the bathymetry and prevailing ice conditions are necessary. In chapter (2), entitled "Exploration of the Arctic Ocean", he describes chronologically the performance and results of important expeditions and interdisciplinary scientific projects of special value for arctic operations. In the chapter (3) the author informs on "Underwater Pingoes, Offshore Permafrost and Ground Ice". Chapter (4), entitled "Underwater Technology", deals with activities at "The Swedish National Defence Research Institute". In the next following subsections the author describes "Remotely-piloted vehicle employed for ship wreck reconnaissance in the High Arctic" and "Operation Greyhound".