NOT SO LONG AGO the subject of life in Alaska was of interest mostly to the diverse band of hippies, hustlers, preachers, roughnecks, dreamers and the assored riffraff who had taken up residence on what travel brochures like to call "America's last frontier." As a result most of the writing was local handiwork that seldom went beyond platitudinous paeans to "my cabin in the wilderness."

But the great changes that have swept across the state in the wake of the trans-Alaska pipeline have roused a broader curiosity about the ways of life that have been usurped and those that still remain in a place where grizzly bears blunder into housing developments and sealskin umiaks bob post off-shore drilling platforms.

Three years ago John McPhee's nonpareil portrait of life in the bush, Coming into the Country , climbed onto the best-seller list. And now Joe McGinniss, author of The Selling of the President and an eclectic handful of other books, offers Going to Extremes to Book-of-the-Month clubbers and others curious about life in "the great land."

McGinniss went north in November 1977 to see what sort of people were drawn to Alaska's extreme cold and isolated life where the land was "unchanged by the presence of man" and to explore the effects wrought by the boom economy. He suspected "the irresistible forces of big business, modern technology, and greed" were engulfing the wilderness, the ancient ways of the Alaska natives and the sense of limitlessness and possibility that lie at the heart of the frontier spirit. His purpose, as he set out, was to record "the last days of the last frontier."

To this grandiose assignment, McGinniss brought has formidable reportorial talents and his gliding, seductive writing style. Unfortunately what he has come up with is little more than a travelogue of impressions, interviews and vignettes with some of the pleasures of the genre but many of its limitations. Having never been to Alaska before, McGinniss knocked around the state for nearly two years as an unabashed "cheechako" -- the slightly disparaging Alaskan term for unseasonsed newcomer. On occasion he turns the pose of impressionable ingenue to his favor with flashes of humor as when he finds his fear of the legendary winter cold has caused him to overdress for a trip in a well-heated pickup truck:

I leaned back, unzipped my parka, unbuttoned by woolen shirt, and lifted by thermal undershirt off my stomach. I was already starting to perspire. The heater fans blasted dry, scalding air into my face. My first day on land in Alaska I had dressed for a journey by dog sled, and had wound up in a hair dryer on wheels."

His astute eye and ear for dialogue serve him well -- most impressively in a chapter about a native woman named Olive Cook who is caught between the culture of her village in western Alaska and her new urban life in Anchorage and later in Washington D.C. McGinniss watches the woman's father engrossed in the construction of a fish trap, weaving and carving in the ways that had been passed down for ages among the native people in the village. Suddenly one of his children cries, "Papa, Papa! Hurry up! Hurry up! 'Six Million Dollar Man' on TV!" and he throws the trap aside. Olive Cook curses the traditional religious cermony in the village at Christmas-time because it interferes with Christmas from Disneyland on the tube. "You can't even watch real Christmas on TV!" she cries, and in that line, McGinniss has captured all of the confusion, ambivalence and dispair that haunt Alaska natives trying to live two lives at once.

Absorbing as some of the chapters are, McGinniss fails to tie them together with anything other than the thread of his travels and thus leaves Going to Extremes without much narrative momentum. The author also seems reluctant to sum up, to examine and to develop some of the themes latent in his material. Perhaps he was constrained by his pose as a cheerful cheechako.

Whatever, Going to Extremes will probably suffer in the shadow of Coming into the Country . Where McGinniss glanced off a dozen towns, McPhee rooted into one and discerned the power of the land that makes it unthinkable to many Alaskans to live anywhere else.

Yet there is a hint in the last and most sustained chapter -- about a wilderness journey into the Brooks Range -- that McGinness has come to sense the spell of Alaska. He moves beyond his journalism of snapshots, postcards and grab-bag impressions, impelled to convey the "mystical" feeling that overtook his party in a mountain basin where no person has ever been. They had found their way in by a labyrinthine route to a hidden place so beautiful it seemed sacred. On that journey the unearthly, dreamlike essence of Alaska came clear: "It seemed we had been given a rare gift of immeasurable value," McGinniss writes. "I turned for one final look. Then, feeling an intense and confusing mixture of joy and sorrow and awe, I turned away again and headed quickly through the rock-walled corridor toward the notch at the end of the ridge that would lead back to the outside world."