We must first rid ourselves of the illusion that penality is above all (if not exclusively) a means of reducing crime and that, in this role, according to the social forms, the political systems or beliefs, it may be severe or lenient, tend towards expiation of obtaining redress, towards the pursuit of individuals or the attribution of collective responsibility. We must analyse rather the ‘concrete systems of punishment’, study them as social phenomena that cannot be accounted for by the juridical structure of society alone, nor by its fundamental ethical choices; we must situate them in their field of operation, in which the punishment of crime is not the sole element; we must show that punitive measures are not simply ‘negative’ mechanisms that make it possible to repress, to prevent, to exclude, to eliminate; but that they are linked to a whole series of positive and useful effects which it is their task to support (and, in this sense,although legal punishment is carried out in order to punish offences, one might say that the definition of offences and their prosecution are carried out in turn in order to maintain the punitive mechanisms and their functions).