A tale of science and discovery on the high, frozen seas. In the summer of 1991, Arms (coauthor, Touching the World, 1975), a writer and sailor, set out on an ocean voyage to explore the Tourngat region of northern Labrador. His passage was unexpectedly blocked by a huge wall of sea ice ""that should not have been there,"" especially in high summer, and especially in the summer of 1991, one of the warmest years in recent record. His awe and perplexity over this untoward occurrence led him to return to the area three years later to seek the reasons why these North Atlantic ocean passages should be clogged with ice out of season and closed to shipping. In the course of his lively narrative, he never provides a single answer, apart from ""the randomness of nature."" Instead, he offers a wonderfully rich account of the mechanics of ocean currents and world weather systems, of the migrations of pilot whales and the minds of sailors far from shore. Arms introduces his readers to such notions as the Great Conveyor Belt theory of oceanic water flow, explains why the Atlantic is saltier and warmer than the Pacific, ponders such climatological anomalies as the ""halocline catastrophe,"" and, closest to his quest, considers the latest scientific reasoning on global warming--the evidence for which phenomenon now appears to be incontrovertible. His science reporting is sound, his eye for meaningful detail sharp. His narrative suffers a bit from long passages of dialogue that go nowhere, but in the end this is a fine study of how complex systems work--and how much closure-seeking science is unable to account for. Fans of popular-science writing and Arctic buffs alike will learn much from Arms's adventure.