This chapter discusses the historical underpinnings and foundations of hostage and crisis negotiation in law enforcement. Historically significant hostage incidents that led to the development of the field are discussed, including the Munich Olympics (1972), Downs v. United States (1971), the Oakdale and Atlanta Prison Sieges (1987), Ruby Ridge and Branch Davidian Standoffs (1992 and 1993), Beslan School siege (2004), the Pulse Nightclub incident (2016), and many others. Significant incidents are presented in a decade-by-decade format that provides for an understanding of the progressive development and refinement of the field. Definitions are given to clarify for the reader what is meant by significant terms, such as hostage versus barricade, crisis, stages of an incident, and so on. The shift from hostage negotiation to crisis intervention/negotiation is discussed. A discussion of the SAFE model and best practices is also included.