DIFFICULTIES IN DETERMINING WHICH INMATES ARE 'DANGEROUS' INCLUDE THE FACT THAT SOME OFFENDERS CONVICTED OF VIOLENT CRIMES WHO HAVE EXHIBITED VIOLENT BEHAVIOR BEFORE INCARCERATION MAY NO LONGER BE DANGEROUS IN THE PRISON SETTING; CONVERSELY, SOME INMATES MAY BECOME DANGEROUS ONLY AFTER CONFINEMENT. SOME EUROPEAN COUNTRIES MAKE USE OF OBJECTIVE CRITERIA, SUCH AS DANGEROUSNESS AT THE TIME OF THE OFFENSE OR INCARCERATION, WHILE OTHERS USE SUBJECTIVE CRITERIA OF SUPPOSED DANGEROUSNESS IN ADDITION. THE NATIONS IN THE FORMER CATEGORY MOST OFTEN INCARCERATE DANGEROUS INMATES IN TRADITIONAL INSTITUTIONS, BUT ISOLATE THEM STRICTLY FROM OTHER INMATES; MOST OF THE COUNTRIES WHICH EMPLOY SUPPOSED DANGEROUSNESS AS A CRITERION HAVE CREATED SPECIAL UNITS WHICH, BY KEEPING DANGEROUS PRISONERS AT A DISTANCE FROM THE REST OF THE INSTITUTIONAL COMMUNITY, REDUCE THE RISK OF DISTURBING THE GENERAL PRISON POPULATION AND ENDANGERING THE SAFETY OF PRISON PERSONNEL. ITALY, BELGIUM, DENMARK, NORWAY, GREECE, AND ICELAND HAVE NOT CREATED SPECIAL SECURITY WARDS, WHILE GERMANY, GREAT BRITAIN, SWEDEN, AUSTRIA, AND FRANCE ASSIGN DANGEROUS INMATES TO PARTICULAR MAXIMUM-SECURITY UNITS. IN ADDITION TO ACTUAL VIOLENT BEHAVIOR AS AN INDICATOR OF DANGEROUSNESS, GREAT BRITAIN AND FRANCE USE MENTAL ABNORMALITY, SWEDEN AND GERMANY USE THE POSSIBILITY OF ESCAPE, AND FRANCE USES PRIOR ESCAPE ATTEMPTS IN WHICH VIOLENCE WAS INVOLVED. REGARDLESS OF THE CRITERIA APPLIED, ALL OF THE COUNTRIES SURVEYED PRACTICE DISPERSION OF DANGEROUS INMATES. CHARACTERISTICS OF SPECIAL FACILITIES IN EUROPE ARE DISCUSSED. IT IS POINTED OUT THAT SECURITY OF THIS SORT IS NOT ADAPTED TO PREPARING THE INMATE FOR REINTEGRATION INTO THE REGULAR PRISON COMMUNITY AND EVENTUALLY INTO SOCIETY, AND THAT ASSIGNMENT TO A SPECIAL UNIT REINFORCES THE CRIMINAL LABEL FOR CERTAIN OFFENDERS. --IN FRENCH.