Flanked by the forbidding, frozen wastes of the Arctic Ocean, Canada's last unknown frontier is under a complex scientific scrutiny by an 80-man expedition -- the Polar Continental Shelf Project. Where the outermost arctic islands shelve down under the heavy rafts of polar pack ice, a team of physicists, geologists, oceanographers and geographers are spending their fifth March-to-September field season exploring a desolate region of thousands of square miles. The northern Queen Elizabeth Islands and the adjacent shallow seas, long thought to be a rich deep-freeze of mineral wealth, are at last giving up their secrets under relentless investigation. With international law ruling that countries claiming coastlines are also entitled to the potential resources of adjoining continental shelves -- the shallow seas nearby -- it was imperative at the beginning of the decade that Canada take inventory of the polar shelf, stake her claim through scientific knowledge. With an operational base established alongside the remote weather station at Isachsen on distant Ellef Ringnes Island, the members of the Polar Shelf Project range far and wide across the frozen seas, the outermost islands and the channels between. By ski-plane, motor toboggan, helicopter, tracked-truck and dog team, Polar Shelf scientists are carrying out an overall study including hydrography, submarine geology, geophysics, geodesy and other sciences. From small, two-man parties set down in a tent on the polar ice 300 miles from land to safaris by convoy of specially-adapted trucks snaking along the frozen channels and offshore seas, Canada is obtaining vital data of economic and strategic importance. In keeping with her geographical position as a nation responsible for large arctic territories, Canada is assessing the region's future and potential wealth. Gathering the knowledge for this task is the work of the Polar Continental Shelf Project.