Although offender profiling can be traced as far back as 1888, when Dr. Thomas Bond attempted to profile the personality of Jack the Ripper, the modern offender profiling approach originated in the 1970s, based on the techniques developed by the Behavioral Science Unit (BSU) of the FBI's Academy at Quantico, VA. The establishment of the BSU was spurred by an apparent trend in an increasing number of serial killings in the United States. Offender profiling was originally intended to assist investigators in either shortening the list of suspects to a small subgroup or by providing new avenues of inquiry. This chapter highlights some of the work that the BSU has done, notably the categorization of crime-scene characteristics and the characteristics of "organized" and "disorganized" perpetrators. As profiling has evolved, particularly in the United Kingdom, it is focusing less on offender characteristics in a given crime and more on the various issues involved in investigating crime. Psychological profiling and behavioral advice currently has a broader focus on detective decisionmaking, intelligence-led policing, investigative interviewing, the handling of informants, and the prioritizing of suspects. The aim is to develop more efficient and effective investigative techniques. In addressing how profiling advice should be presented to investigators, the chapter suggests a structure for a high-quality profiling report. The chapter advises that a profiling report should be systematically evaluated by the investigative team in order to assess its relevance and clarity. Criteria for such an evaluation are offered. The checking of a profiler's credentials and legal/ethical concerns in profiling are also discussed. 26 references and appended sample profiling report and codes of conduct for offender profiling