The document discusses the critical importance of infrastructure systems like power plants, water treatment facilities, and transportation. It notes that these systems now face growing cybersecurity risks like Stuxnet and other attacks that could endanger lives and cause billions in damages. The document provides examples of past attacks on infrastructure systems dating back to the 1990s that impacted facilities like power plants and water treatment. It emphasizes that infrastructure systems are becoming more exposed to threats as they become more networked and integrated.