*The role components of policing discussed in the preceding sections are all of a formal nature. That is, neither the restriction of occupational duties to serious police work and its licensing as a marketable occupation, nor the severance of ties with military origins and alignment with academic scholarship, nor the institution of the emphasis on educational requirements, specify what a policeman must know and what he must be able to do, in substantive terms. It was merely proposed that the introduction of these formal role components will further the development of a disciplined and explicit body of knowledge and technical skill, and that without introducing them such a development is not likely to take place. But it is possible to go beyond that to the tracing of fragmentary outlines of substantive knowledge and technique, albeit merely in a tentative manner and mainly for purposes of further exploration. In the following remarks, we will attempt to sketch several elements or aspects of what appears to be professional, purposeful, and responsible police work. It is important to emphasize that, in accordance with our earlier expressed view, the substance of police professionalism must issue mainly from police practice and police experience; none of the points discussed is based on purely invented desiderata. Indeed, the following features of police work are not being presented as necessary and proper in the same sense as the formal role components dis‐ cussed in the foregoing three sections. Instead, they are presented because there seems to attach to them a sense of rationality and methodicalness. What com‐ mends them is not that they are right but that they are based on reason, rather than on feeling, and in this sense professional. All of the following topics are based on observations of police practice and on extended conversations with * DHEW Publication Number (HSM) 72–9103. We thank Lisa D. Alberts, NIMH Clearance Officer, for her advice.