IN 1833, MARC FIRST DESCRIBED THE CONDITION OF PYROMANIA AND SUGGESTED THAT THIS FORM OF ARSON WAS MOST LIKELY TO BE OBSERVED IN SEXUALLY-FRUSTRATED TEENAGE COUNTRY GIRLS AND ALSO IN OLDER MEN WHERE IT WAS RELATED TO THE ACHIEVEMENT OF SEXUAL SATISFACTION. THE ASSOCIATION BETWEEN FIRE AND SEXUALITY WAS FURTHER DEVELOPED THROUGH THE WORK OF FREUD. FORENSIC PSYCHIATRISTS, CLINICAL PSYCHOLOGISTS, AND SOCIOLOGISTS HAVE ALL MADE SIGNIFICANT CONTRIBUTIONS TO BOTH THE ETIOLOGY AND TREATMENT OF ARSON AND ARSONISTS. UNDER THE CRIMINAL DAMAGE ACT OF 1971, A PERSON WHO DESTROYS OR DAMAGES PROPERTY BELONGING TO ANOTHER WITHOUT LAWFUL EXCUSE IS GUILTY OF AN OFFENSE PUNISHABLE WITH IMPRISONMENT FOR A MAXIMUM OF 10 YEARS. IF DESTRUCTION OR DAMAGE IS BY FIRE, THE OFFENSE CONSTITUTES ARSON AND IS PUNISHABLE WITH A MAXIMUM SENTENCE OF LIFE IMPRISONMENT. THE NUMBER OF REPORTED ARSON CASES HAS ALMOST DOUBLED BETWEEN 1971 AND 1975. SOME BUILDINGS ARE NOT ADEQUATELY PROTECTED AGAINST FIRE, AND THE MEDIA HAVE PLAYED AN IMPORTANT ROLE IN THE PUBLIC'S TAKING CRIME FOR GRANTED AND ACCEPTING IT. IN ADDITION TO PYROMANIA, TERMS USED TO DESCRIBE ARSON ARE INCENDIARISM AND MALICIOUS FIRE RAISING OR MALICIOUS IGNITION. THE LATTER TERMINOLOGY COVERS FIRE RAISING COMMITTED FOR FINANCIAL REWARD OR TO COVER UP ANOTHER CRIME, FIRE RAISING FOR POLITICAL PURPOSES, SELF-IMMOLATION AS A POLITICAL GESTURE, AND FIRE RAISING COMMITTED FOR PATHOLOGICAL REASONS OR FOR MIXED MOTIVES. CONVICTED ARSONISTS, IN COMMON WITH MOST OTHER OFFENDERS, ARE PREDOMINANTLY MALE. CHARACTERISTICS OF ARSONISTS EMPHASIZE THE NEED FOR DIFFERENTIAL DIAGNOSIS SINCE PSYCHIATRICALLY DISTURBED PERSONS AND THOSE FOR WHOM ARSON IS ONE ASPECT OF A MULTIFACETED HANDICAP REPRESENT DIFFERING TYPES OF ARSONISTS. SUPPORTING DATA AND REFERENCES ARE PROVIDED. (DEP)