The police force represents the external layer of criminal justice administration, the entry point for criminals, the conduit of information about crime, and the most immediate picture of the system to society. For this very important part of the system, criminological training would help to define, diagnose, and qualify types of crimes and criminals. As a crossroads science, criminology brings together social control, penal persuits, biology, economy, and medicine, and can offer the police force and its officers the theory and understanding that they need to complement their work on the field. Somehow, police, complaining of a lack of understanding by the rest of the justice administration of their work, and the adminisrtation, misunderstanding the police position, need to contribute together to practical communication among themselves and with researchers from criminology. Police too seldom receive sound inservice and continuing education in much-needed criminological subjects. And researchers in criminology could benefit from both the statistical information that police forces have to offer to scientific study and from the first-hand, observational kinds of information that police officers have from their work in the field. Thus there is the potential for penetrating the justice administration with criminological findings, with both the police and criminologists benefiting from the contact. Sixteen references are provided. --in French.