ARSONISTS MAY BE CLASSIFIED INTO THREE MAJOR GROUPS: (1) ARSON-FOR-PROFIT FIRE SETTERS; (2) SOLITARY FIRE SETTERS; AND (3) GROUP FIRE SETTERS. VERY LITTLE IS KNOWN ABOUT THOSE INVOLVED IN ARSON FOR PROFIT. IT IS ARGUED THAT BOTH THE BUSINESSMAN WHO SETS FIRE TO HIS OWN BUSINESS TO COLLECT INSURANCE AND THE PAID ARSONIST ARE ENGAGING IN RATIONAL ACTS. THERE ARE MANY TYPES OF SOLITARY FIRE SETTERS. THERE IS THE SOLITARY FIRE SETTER WHO BURNS OUT OF REVENGE OR SPITE, AND THERE IS THE PYROMANIAC WHO DERIVES SENSUAL SATISFACTION FROM HIS ACT. THERE IS ALSO THE INDIVIDUAL WHO WANTS TO BE A HERO AND SETS FIRES IN ORDER TO HELP PUT THEM OUT. FINALLY, THERE IS THE PSYCHOTIC. GROUP FIRE SETTINGS ARE CLASSIFIED INTO THREE CATEGORIES: (1) POLITICAL FIRES; (2) VANDALISM FIRES; AND (3) RIOT FIRES. MOST ARSONISTS ARE VIEWED AS PSYCHOPATHS POSSESSING THREE MAJOR CHARACTERISTICS: (1) THEY OFTEN APPEAR NORMAL AND LEAD REASONABLY NORMAL LIVES; (2) THEY APPEAR TO LACK FEELINGS OF CONCERN FOR OTHERS; AND (3) THEY OFTEN DO NOT RESPOND TO PUNISHMENT. CHARACTERISTICS OF ARSONISTS WERE EXAMINED IN AN EFFORT TO BETTER UNDERSTAND THE CRIME. ARSONISTS OFTEN COME FROM BROKEN OR DISRUPTIVE HOMES, AND FREQUENTLY HAVE LIVED UNDER HARSH OR FRUSTRATING CONDITIONS. MANY FIRE SETTERS HAVE COMMITTED OTHER CRIMES. LOW INTELLIGENCE AND LACK OF ACHIEVEMENT ARE OFTEN ASSOCIATED WITH AN ARSONIST PERSONALITY. SEXUAL AND SOCIAL INADEQUACIES AND BEDWETTING AS A CHILD ARE ALSO OFTEN CORRELATED WITH FIRE SETTING. MOST OF THE LITERATURE ON ARSONISTS IS FROM STUDIES CONDUCTED 25 YEARS AGO, AND MORE CURRENT INFORMATION IS BADLY NEEDED. FOOTNOTES ARE INCLUDED THROUGHOUT THE TEXT. (MLC)