Arson is a major source of property damage, injury and death in the United States. Many people who commit arson have extensive psychiatric histories and symptoms at the time of their fire-setting. However, traditionally the law enforcement community and the mental health community have not shared information about the characteristics of people who set fires. This study examined mental health records and/or prison files from 283 arsonists. 90% of arsonists had recorded mental health histories, and of those 36% had the major mental illness of schizophrenia or bipolar disorder. 64% were abusing alcohol or drugs at the time of their firesetting. Pyromania was only diagnosed in three of the 283 cases. Different motives for setting fires are discussed; many patients were both angry and delusional. A survey instrument, which captures both psychiatric and legal data, is included. Suggestions are made for gathering future "profiling" information. A matrix approach to coding diagnosis and behavior is presented.