This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book focuses on agents that may cause cancer. It also focuses on risks as a result of exposure to low levels of cancer-causing agents. The book argues that the role of the dose-response assessment in the risk-assessment process needs to be reconsidered. It discusses the process of risk management as a health, safety, and socioeconomic enterprise. The book also discusses problems of uncertainty and the difficulties encountered when large dose extrapolations are employed. The greatest risk in life is being born. Being born a normal, healthy child is only a 50–50 proposition. Risks associated with automobile travel, airline travel, natural disasters such as forest fires or tornadoes, and industrial pollution are examples of consequences that are not entirely controllable by individuals. Risk management lays out alternative strategies to reduce the risks.