The term "profiling" was regularly used by members of the Federal Bureau of Investigation's (FBI) Behavioral Science Unit who defined it as the process of drawing inferences about a suspect's characteristics from details of his or her actions exhibited during the commission of a crime. While it is easy to view the pioneering work of Brussel as being of historical interest only, a close examination of his memoir provides insights into his methods of profile construction that suggests similarities with current Behavioural Investigative Advice practice. The very use of the term "profiling" is almost synonymous with the work of the FBI's Behavioral Science Unit and its successor units. The criminal investigative analysis process in regard to offender profiling has been described in varying degrees of detail in different publications through the years. The adaptive mode occurs when external events become the source of interaction or conflict, whereby the individual attempts to change the external circumstance.