This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book provides an introduction to process safety, and states the importance of process safety as illustrated by process safety incidents. Organizations in the process industries have a long-standing concern for process safety. The concept of process safety management evolved as the chemical process industries matured their focus on process safety. The book describes basic concepts of fire, explosion, toxics, reactive chemicals, and other hazards along with where to find data on hazardous properties of materials and metrics used to classify incidents involving those materials. It introduces consequence analysis and risk assessment concepts along with methods to mitigate risk. The book addresses the topics of human factors, operational readiness, management of change, operating procedures, conduct of operations, safe work practices, and emergency management.