By early April 1914, Colorado Governor Elias Ammons thought the violence in his state’s strike-bound southern coal district had eased enough that he could begin withdrawing the Colorado National Guard, deployed six months earlier as military occupiers. But Ammons misread the signals, and on April 20, 1914, a full-scale battle erupted between the remaining militiamen and armed strikers living in a tent colony at the small railroad town of Ludlow. Eight men were killed in the fighting, which culminated in the burning of the colony. The next day, the bodies of two women and eleven children were found suffocated in a below-ground shelter. The “Ludlow Massacre,” as it quickly became known, launched a national call-to-arms for union supporters to join a ten-day guerrilla war along more than two hundred miles of the eastern Rockies. The convulsion of arson and violence killed more than thirty people and didn’t end until President Woodrow Wilson sent in the U.S. Army. Overall at least seventy-five men, women, and children were killed in seven months, likely the nation’s deadliest labor struggle. In Blood Passion, journalist Scott Martelle explores this little-noted tale of political corruption and repression and immigrants’ struggles against dominant social codes of race, ethnicity, and class. More than a simple labor dispute, the events surrounding Ludlow embraced some of the most volatile social movements of the early twentieth century, pitting labor activists, socialists, and anarchists against the era’s powerful business class, including John D. Rockefeller, Jr., and helped give rise to the modern twins of corporate public relations and political “spin.” But at its heart, Blood Passion is the dramatic story of small lives merging into a movement for change and of the human struggle for freedom and dignity.