In 1919, four million workers launched the greatest strike wave in American history. Boston policemen, New England telephone operators, textile workers up and down the East Coast, most of the workingmen and women in Seattle, 450,000 coal miners, and 365,000 steelworkers nationwide led an offensive in which more than one in five American workers eventually participated. Their goals were both material and ideological. Fearing retrenchment by management after World War I, workers fought to defend their wartime wages and hours but even more basically to protect their jobs. And inspired by America's war effort in Europe, they sought to bring the campaign for democracy back home, to their own shop floors and election wards.

Chicago, with its history of labor militance and its location at the crossroads of transportation and communication, became a center of the strike movement, with more strikes than any other city besides New York. Here, too, some of the most important strikes took place, particularly in the mass production industries – steel, meatpacking, readymade clothing, and agricultural equipment – that had made Chicago the second largest industrial area in the nation.