FIRST DESCRIBED AFTER A 1973 SWEDISH BANK ROBBERY IN WHICH FOUR BANK EMPLOYEES WERE HELD HOSTAGE FOR 131 HOURS, THE SYNDROME HAS THREE PHASES: FIRST, HOSTAGES DEVELOP POSITIVE FEELINGS TOWARD THEIR CAPTORS, USUALLY AFTER THE PASSAGE OF SOME TIME WITHOUT VERBAL OR PHYSICAL ABUSE; SECOND, ACCOMPANYING NEGATIVE FEELINGS TOWARD THE POLICE DEVELOP AS THE VICTIM IDENTIFIES WITH THE AGGRESSOR; AND THIRD, THE CAPTORS MAY RECIPROCATE THESE FEELINGS. THE PSYCHOLOGICAL THEORIES OF SIGMUND AND ANNA FREUD EXPLAIN THE SYNDROME IN TERMS OF EGO DEFENSE UNDER EXTREME AND UNEXPECTED TRAUMA AND DEPENDENCE ON THE CAPTORS. ACCORDING TO ANNA FREUD, THE SYNDROME DEVELOPS FOLLOWING OTHER STAGES OF HOSTAGE REACTION. THE STAGES BEGIN WITH DENIAL OF REALITY, OFTEN MANIFESTED BY SLEEPING, AND CONTINUE WITH DELUSIONS OF REPRIEVE, BUSY WORK SUCH AS KNITTING OR COUNTING, AND TAKING STOCK OF ONE'S LIFE. THE SYNDROME'S VARYING INTENSITY, AND OCCASIONAL ABSENCE, IS ILLUSTRATED BY CASE EXAMPLES INVOLVING HIJACKING, A PRISON BREAK, BANK ROBBERY, AND ABDUCTION. POLICE NEGOTIATORS DEALING WITH HOSTAGE SITUATIONS SHOULD USE THEIR KNOWLEDGE OF THIS SYNDROME TO SAVE THE LIVES OF ALL PARTICIPANTS, INCLUDING THE HOSTAGES, THE CROWD OF ONLOOKERS, THE POLICE OFFICERS, AND THE OFFENDERS. MEANS TO ACCOMPLISH SUCCESSFUL OUTCOMES INCLUDE ESTABLISHING INNER AND OUTER PERIMETERS, POLICE TRAINING, DISCIPLINE AND PROPER EQUIPMENT, AND NEGOTIATIONS WHICH FOSTER THE DEVELOPMENT OF THE SYNDROME BY EMPHASIZING THE HOSTAGE'S HUMAN QUALITIES TO THE CAPTORS. THE HOSTAGE'S SUBSEQUENT HOSTILITY TO THE POLICE IS TO BE EXPECTED AND ACCEPTED BY THE POLICE. REFERENCES ARE INCLUDED IN THE EXTENSIVE FOOTNOTES. (CFW)