Barometer Rising was the first novel published by Hugh MacLennan, arguably Canada's most significant novelist of the middle of the twentieth century and certainly its most recognized. First published (New York: Duell, Sloan and Pearce) in 1941 amidst the turmoil of the Second World War, the novel is set during the First World War, not on the battlefields of Europe but in Canada before, during and after the Halifax Explosion, which destroyed much of that city's north end on the morning of December 6, 1917. MacLennan himself was a survivor of the Explosion, and drew on his own memories as a boy of 10 who witnessed the destruction. Barometer Rising marks a shift in MacLennan's writing from works with international themes - which failed to find publishers - to the decidedly nationalist theme that occupies his major works.

Barometer Rising is an allegory of Canada's shift away from the political and cultural influences of colonial, Imperial Britain to a decolonized independence and emergent national consciousness throughout the course of the First World War. The mythological template of Homer's Odyssey is clearly in evidence throughout the book; the tale of a hero's return and redemption is also the narrative of a culture's coming of age. Protagonist Neil MacRae returns to Nova Scotia from the battlefields of Europe, where his body, mind and reputation have been battered. His morally bankrupt Anglophile uncle, Geoffrey Wain, the former colonel of his regiment, has blamed him for the failure of an attack and MacRae is under threat of prosecution and execution for cowardice. While MacRae and Penelope Wain, who is the colonel's daughter and MacRae's former lover, seek to clear his name, Col. Wain seeks to bury the past and profit from the opportunities the war presents. The Explosion literally blows the old order apart, disintegrating its cynicism and hollow ideals, and affording MacRae the chance to emerge an active hero for a new generation and a country on the brink of renewal. At the end of the novel MacRae and Penelope Wain are poised to depart from "old" Halifax for the dynamic potential of the westward regions of the country.

Certainly, the novel has had its share of criticism. George Woodcock, classifying it as "romantic realism," noted MacLennan's relative conservatism, in contrast to literary movements of the time; his works' didacticism and sometimes simplistic characterization; and their reliance on local colour and on coincidence. Barometer Rising has aged better than many of MacLennan's works, but nevertheless contemporary critics and readers often find the quality and tone of his nationalism jarring: Barometer Rising suggests the new role of Canada is to be a bridge between Britain and America. The book's portrayal of women, particularly Penelope Wain, is restrictively traditional and unsatisfying: through the course of the novel she moves from being an active participant in the modern age, an independent woman working as a ship designer, to a silent maternal helpmeet in the final passages.

Nevertheless, Barometer Rising's immediate popularity - sufficient to allow MacLennan to leave his teaching post at Lower Canada College - has not waned; it remains beloved by Canadian readers who savour MacLennan's skilled and powerful evocations of the atmosphere of wartime Halifax, of the chaotic horror of the explosion and its aftermath, and the heroic efforts of the survivors. Further, by the middle of the twentieth century Canadian readers were hungry for Canadian subjects; Barometer Rising announced a turn in literary production in Canada to consciously Canadian stories about the growing nation and its people, which continued in a flowering of Canadian literary nationalism in the following decades (SeeLiterature in English).