Over a 40-year career that includes the pivotal 1970s novel, 92 in the Shade, Thomas McGuane’s work has grown leaner and more mature, while continuing to juggle over-the-top comedy and heartbreaking tragedy. In Crow Fair, his new collection of short stories set mostly in Montana’s Big Sky country, McGuane depicts better than most what one character thinks of as “the blizzard of things that could never be explained and that pointlessly exhausted all human inquiry.”