This book shows how inflation can disrupt politics and society. With no recent precedent, mild inflation spurred mass protests, myriad remedial schemes, and partisan political reversals between 1910 and 1914. Then wartime demand and inflationary fiscal policy doubled consumer prices from 1915 to 1920, triggering waves of strikes, food riots by immigrant housewives, class conflict, and elite fears of revolution. Middle-class households resented falling real incomes. Even more than today, food prices dominated consumer concerns. Yet farmers wanted high commodity prices. Accordingly, both sides blamed and attacked meatpackers, wholesalers, and retailers. Then as now, inflation hurt whichever party held the White House. Fumbling responses by Wilson administration and the Federal Reserve led to hesitant price controls, punitive raids and prosecutions, and a now-familiar fallback—high interest rates in 1920 and subsequent recession. An epilogue traces continuing popular and politicalresponses to changes in the consumer price index down to 2020.