Urban conflagrations, such as the Great Chicago Fire in 1871 and the Great Boston Fire of 1872, terrorized the citizens of nineteenth-century American cities, although rebirth in the aftermath offered a chance to shape the future. Ultimately, urban dwellers and planners created sweeping changes in the methods of constructing buildings, planning city streets, engineering water distribution systems, underwriting fire insurance, and firefighting itself. The practical knowledge gained from fighting nineteenth-century fires gave form and function to modern fire protection efforts. Changes in materials and building design resulted directly from tragedies such as fires in fireproof hotels. Thousands of buildings burned,millions of dollars were lost, the fire insurance industry faltered, and a tradition of volunteerism died out before municipal authorities accepted the necessary changes. The great fires formed a crucible of learning for firefighters, engineers, architects, and underwriters. Bruce Hensler shows how the modern American fire service today is a direct result of the lessons of history.