NONFICTION - Dec. 13, 1992

THIS HOUSE OF SKY by Ivan Doig (Harcourt Brace Jovanovich: $24.95; 314 pp.) Only when a way of life is vanishing does it begin to seem worth writing about. The window of opportunity is narrow. Ivan Doig grew up on Montana ranches, but he had to go away to college--become an outsider--to recognize that life as a literary subject, and by then the real insiders were almost gone. Doig’s father, Charlie, dying of emphysema, gasped out stories into a tape recorder; his maternal grandmother, Bessie Ringer, added others; Doig filled in the gaps by ransacking his own memories and those of decrepit ex-cowboys and saloonkeepers who had known his family decades before.

The result was “This House of Sky,� the memoir whose appearance 15 years ago established Doig as one of the leading “sagebrush writers�--modern folks who write about the rural West without necessarily writing Westerns. Since then, he has become known for novels (“Dancing at the Rascal Fair,� “Ride With Me, Mariah Montana�), but “Sky� has quietly retained its appeal. Hence this anniversary edition.

In retrospect, “Sky� seems an unlikely debut--a long book that shies away from most of the commercial kinds of excitement. What distinguishes it, besides a wealth of detail, is a lyrical style muscled with active verbs (“A bow of meadow makes the riffled water curl wide to the west. . . . A low rumple of the mountain knolls itself up watchfully�) and what reveals itself to be a story of uncommon devotion.