In the early twentieth century, politicians and policy makers singled out Port Arthur and Fort William (present-day Thunder Bay) as breeding grounds for revolution, as places where new immigrants suffered harsh conditions in dockyards, lumber mills, and railway yards, much to the benefit of radical labour organizations. This intensely engaging history reasserts Northwestern Ontario’s rightful reputation as a birthplace of leftism in Canada by exposing the conditions that gave rise to an array of left-wing organizations, including the Communist Party, the One Big Union, and the Industrial Workers of the World. Yet, as Michel Beaulieu shows, the circumstances and actions of Lakehead labour, especially those related to ideology, ethnicity, and personality were complex; they simultaneously empowered and fettered workers in their struggles against the shackles of capitalism. Cultural ties helped bring left-wing ideas to Canada but, as each group developed a distinctive vocabulary of socialism, Anglo-Celtic workers defended their privileges against Finns, Ukrainians, and Italians. At the Lakehead, ethnic difference often outweighed class solidarity – at the cost of a stronger labour movement for Canada. An original account of working-class politics at the beginning of “Canada’s century,” Labour at the Lakehead reveals that ethnic differences often outweighed class allegiances – at the cost of greater solidarity for Canada’s left.