The study was prompted by recognition that although pyromania has been explicitly defined in successive editions of the American Psychiatric Association's Diagnostic and Statistical Manual since 1980, it is an elusive concept. Psychiatrists rarely diagnose pyromania, but police and fire personnel often use it. The 603 participants were taking part in training focusing on the motivational and methodological characteristics of serial arson and on the traits of serial arsonists. When the trainer reached the section on motives, participants were asked to fill out a card indicating their occupation, age, gender, years of experience in their occupation, and open-ended definition of pyromania. The data were analyzed by means of a content analysis that focused on crucial terms; an assessment of whether it correctly the five diagnostic manual criteria for pyromania and whether any motive was specifically violated; and an analysis of the specific elements of each diagnostic criterion. Results indicated a remarkably poor understanding of pyromania. The researchers also examined the sources of information available to law enforcement and fire fighting/investigation professionals and determined that the sources were generally as misinformed as the professionals were. Findings indicated that the professions of psychiatry, law enforcement, and fire fighting/investigation need better source material and must share information better if they are to reduce the threats posed by the ineffectual differentiation of the causes of serial arson. Table and 39 references (Author abstract modified)