During the Second World War, the Congress of Industrial Organizations in Canada grew from a handful of members to more than a quarter-million. What was it about the “good war” that brought about this phenomenal growth? Labour Goes to War argues that both economic and cultural forces were at work. Labour shortages gave workers greater economic power in the workplace. But cultural factors – workers’ patriotism, ties to those on active service, and allegiance to the “people’s war” – also fueled the CIO’s growth. The complex, often contradictory, motives of workers during this period left the Canadian labour movement with an ambivalent progressive/conservative legacy.