The continuing existence of the criminal phenomenon is a great challenge to the human mind. For despite the fact that man, after nearly two centuries of scientific and technical progress, has at last triumphed over his natural environment, so far he has not eliminated crime. There is nothing more permanent in the social organization than the prison budget : “good year, bad year, a certain number of individuals are locked up behind bars,” said Quetelet as far back as the middle of the XlXth Century—a century, however, that witnessed the most spectacular progress in all fields. Since then, because of the evolution of western moral philosophy, whether inspired by problems of philanthropy, mental and social hygiene, scientific research or, as now, public order, minds have stood up to this challenge—albeit without much evidence of success. Most reform movements were inspired by an optimistic view of man and society, believing in their infinite perfectibility; these were heirs to the philosophy of Jean-Jacques Rousseau, whose counterpart in the field of biology was Darwin and in ihe field of economics, Karl Marx. The social sciences were conceived in this context, and in order to specify the social forces shaping man's destiny according to a determinist hypothesis, they proposed to furnish the tools for the establishment of a social order that would eliminate the scandalous material and moral ills of society. Criminology, too, was born in this same context; Lombroso and Ferri, the Darwinian biologist and the Marxist sociologist, oriented our discipline toward the conquest of pathological and anti-social forces. It is true that Durkheim took a more moderate position, crime being for him a normal phenomenon linked with the functioning of society, and Tarde had an even more pessimistic view, considering his adherence to the idea of free will and his Christian concept of human nature, always exposed to the forces of evil. Nevertheless, the predominant thought, especially of those who were oriented towards action, was inspired by this first tradition.