As a forensic psychologist, most topics involving the interaction of the criminal justice system with the science of psychology interest me. It was not until the start of the 1990s, however, that I first learned of a fascinating and purportedly new technique whereby police investigators could develop a description of an offender based not on any witness report, but on behaviors evidently displayed during the commission of a crime. What captured my attention most about this technique was the context in which it was applied. Often, work and research in the domain of forensic psychology considers issues in a reactive context. Examples include psychological evaluations of an individual for the purpose of an insanity defense or a person’s potential for recidivism in the context of a parole hearing. Here, however, was something that could be used in a proactive context, while a criminal investigation was still very much afoot. The disciplinary knowledge of psychology could in this sense be used to compile a description of the likely offender to assist with an on-going investigation. This remarkable concept or investigative tool as police referred to it was simply referred to as psychological profiling. I quickly learned, however, that although the underlying concept surrounding this technique was the same, the title assigned to it varied markedly depending on differing practitioners and their disciplinary backgrounds, which was often reflected in the nomenclature adopted by these practitioners. The terms criminal profiling, offender profiling, criminal investigative analysis, and criminal personality profiling all seemed to be used interchangeably to describe the practice. With this new awareness (of what I will for the sake of simplicity refer to here as "profiling"), I set about collecting, reading, and learning as much as I could about the technique. Initially, I was thoroughly captivated by the material. The prospect of being able to deduce the identity of a criminal and thereby assist in the investigation of violent crime was of great interest to me and, I considered, of enormous practical benefit to law enforcement agencies throughout the world. However, after about 6 months of exploring the available literature doubts began to creep into my mind as I contemplated the research on the topic.