High in the roadless mountains of Idaho's Primitive Area there is a wild stretch of water that dives and twists 113 miles through the canyons of the Salmon River Mountains. In 1937 Dr. Russell Frazier put in at its headwaters in Bear Valley, Idaho and came safely out the other end. But because the unwary can still get caught in its lethal traps, the Middle Fork, for good and gloomy reasons, is called the River of No Return. The title, fortunately, carries no terror for the people of Idaho, half of whom seem to boat on the Middle Fork during the months of July and August. Some of them, lounging majestically in varnished fishing chairs, cast for salmon and trout while their double-ended river boats slither between the rocks. Others, like these Explorer Scouts (left), pile into rubber rafts and go bouncing happily through the boiling rapids, upside down half the time, soaking wet the rest, and not at all concerned with No Return.