In one of phrenology's basic texts, a case is cited of a Dutch fiddler who confessed to 34 murders, which he claimed to have committed simply because he derived pleasure from killing other human beings. At a time when most people would have explained the Dutch fiddler's behavior from a metaphysical and theological perspective, i.e., as wanton sin, phrenologists attributed it to innate biological defect. Breaking from theological interpretations of human behavior, phrenologists adopted the previously developed methods of the natural sciences, assuming that the social world could be studied with the same procedures. Thus, phrenology was an effort to break with older metaphysical and theological explanations of behavior and replace them with an empirical science. In viewing phrenology, modern criminologists have three options of response: ignore it, make it "relevant," or come to terms with it. This article proposes the latter response. In pursuing this approach, this article first establishes the socio-political context in which phrenology emerged and then summarizes the doctrine, emphasizing those aspects relevant to criminology and criminal justice. It then discusses phrenologists' explanations of crime, their criminal jurisprudence, and their penology. A summary of phrenology's achievements in the areas of criminology and social control is followed by remarks on reasons for the doctrine's eventual failure. The article then considers the "bad science" issue, arguing that if criminology welcomes its apparently disreputable forerunners into its history, it will be better able to understand both its own identity and the nature of its scientific enterprise. 17 notes and 87 references