The Johnstown Flood (1968) by David McCullough is a detailed account of the catastrophic 1889 flood that devastated Johnstown, Pennsylvania, killing over 2,200 people. The flood was caused by the collapse of the South Fork Dam, which had been weakened by years of neglect and modifications made by private speculators. Despite warnings and attempts to save the dam, it broke after record rainfall, releasing almost four billion gallons of water, which swept through the town and its surroundings with devastating force. McCullough's narrative examines the social, political, and economic factors that contributed to the disaster, highlighting themes of negligence, greed, and inequality. Through interviews with survivors and meticulous research, McCullough chronicles this avoidable tragedy, one of the deadliest in U.S. history, while exploring the aftermath, including the legal battles and changes in liability law.