SPECTACULAR CASES OF BANDITRY IN WHICH HOSTAGES ARE TAKEN HAS INCREASED PUBLIC FEAR, BUT NO LAWS HAVE BEEN PASSED TO REGULATE THE NEW CRIME FORMS. AS BANDITRY IS NOT A SPECIFICALLY DEFINED OFFENSE IN THE CRIMINAL CODE, POLICE FACE A DIFFICULT PROBLEM IN DEALING WITH SUCH CRIMES. IN THE 20TH CENTURY CONTROL EFFORTS HAVE INCLUDED SPECIAL MEASURES TO REGULATE ACTIVITIES OF ITINERANTS AND STUDIES TO GAIN INFORMATION ON THE UNDERWORLD AND ITS OPERATION. THREE GROUPS OF MODERN CRIMINALS HAVE BEEN DIFFERENTIATED: (1) ORDINARY CRIMINALS WITH A FIXED PATTERN OF OPERATION, (2) MEMBERS OF UNDERWORLD GROUPS, AND (3) AMATEUR BANDITS. BANDITRY ACTIVITIES AND DYNAMICS ARE COMPLEX; INTEGRATION OF PARTICULAR INDIVIDUALS DEPENDS ON THE SERVICES WHICH THEY CAN RENDER. PROFESSIONAL BANDITS ARE CHARACTERIZED BY SUPERFICIALLY RESPECTABLE LIVING PATTERNS WHICH DO NOT ATTRACT ATTENTION, FLEXIBILITY IN EXPLOITING THE VICES OF 'HONEST PEOPLE,' ATTENTION TO DETAIL IN PLANNING CRIMES, AND RELATIVE STABILITY IN THE COMPOSITION OF THEIR GROUPS. POLICE HAVE BECOME INVOLVED IN STUDIES OF CRIMINAL PERSONALITY BECAUSE THEY MUST FREQUENTLY SUPPLY BACKGROUND INFORMATION ABOUT OFFENDERS AT THE REQUEST OF EXAMINING MAGISTRATES ACCORDING TO PROVISIONS OF THE CRIMINAL CODE. THE JUVENILE POLICE UNIT IN TOULOUSE MAINTAINS FILES ON JUVENILE DELINQUENTS TO KEEP TRACK OF THEIR CRIMINAL CAREERS AND TO COLLECT CONFIDENTIAL INFORMATION ON FORMATIVE INFLUENCES. INDEX CARDS COLOR CODE PREVIOUS ADDRESSES AND INFORMATION ON FAMILY INVOLVEMENT IN CRIME. A COMPARISON OF RESULTS OF PERSONALITY RESEARCHERS CONDUCTING PRISON INTERVIEWS) INDICATES THAT INEXPERIENCED OFFENDERS WARM UP TO RESEARCHERS, TALKING OPENLY ABOUT FAMILY AND FRIENDS AFTER SEVERAL SESSIONS, WHILE THE PROFESSIONAL CRIMINAL READILY ADJUSTS TO PRISON AND RETAINS AN ATTITUDE OF RESISTANCE TOWARDS RESEARCHERS. UNFORTUNATELY, JUDGING THE STAGE OF A PARTICULAR CRIMINAL CAREER IS VERY DIFFICULT, AND SEVERAL POLICE OPINIONS SHOULD BE SOUGHT. FOR RELATED DOCUMENT, SEE NCJ #55985. --IN FRENCH. (KMD)