SCHEMATICALLY ONE MAY PRESENT THE EVOLUTION OF THE CONCEPTIONS REGARDING JUVENILE DELINQUENCY AS FOLLOWS: THE JUVENILE DELINQUENT HAS BEEN CONSIDERED AS AN ADULT CRIMINAL IN MINIATURE, A VICIOUS AND PERVERTED HUMAN BEING, AN UNFORTUNATE BEING, A VICTIM OF SOCIAL INJUSTICE, A MALADJUSTED CHILD, A SICK OR ABNORMAL BEING, A BEING WHICH BELONGS TO A MALADJUSTED FAMILY, AND A BEING WHICH BELONGS TO A SICK SOCIETY. THE AUTHOR SPEAKS ABOUT THE DIFFERENT FORMS OF SOCIAL MALADJUSTMENT WHICH CAUSE THE NEW FORMS OF JUVENILE DELINQUENCY: THEFT IN DEPARTMENT STORES, THEFT OF MOTOR VEHICLES FOR USE, BURGLARY, VANDALISM, SEXUAL DELINQUENCY, TRAFFIC DELINQUENCY, VIOLENCE, TRAFFIC OF DRUGS. ANALYSED ARE THE NEW APPROACHES OF THE AUTHORITIES CHARGED WITH PENAL AFFAIRS OF YOUNG PEOPLE AND THE NEW TECHNIQUES OF THEIR TREATMENT. THIS EVOLUTION BELONGS TO A GENERAL EVOLUTION AND TO A PROGRESSIVE TENDENCY IN A PLURALISTIC SOCIETY, WHICH WILL BE TOLERANT, LIBERAL, EGALITARIAN AND WHERE HIERARCHIC VERTICAL STRUCTURES ARE SUBSTITUTED BY MORE DEMOCRATIC AND HORIZONTAL ONES. (AUTHOR ABSTRACT MODIFIED) --IN FRENCH. SUMMARIES IN ENGLISH, FRENCH, AND GERMAN