The study combines statistical research methods with interviews. The basic statistical data are provided by the crime report registers in Helsinki, Espoo, and Vantaa (the three main municipalities that form the Helsinki metropolitan area); the identifying-feature register; method-of-operation register; and suspect register maintained by the National Bureau of Investigation. Interview and observation data come primarily from the police officers working in the drug office of the Helsinki Criminal Investigation Police, as well as drug users and other persons involved in the drug markets. The study shows that the Helsinki drug markets as a whole are not highly organized and are in a constant state of flux, due in part to the fact that there are no fixed organizations in the area. Despite the general unsettled state of the drug markets, however, there are persons able to organize the import and distribution of large amounts of drugs. There is no constant stream of entrepreneurs trying to enter Finnish drug markets, nor is there a need to fight for market share. Regarding drug-related crime, persons suspected of serious drug offenses do not have as great a tendency as those suspected of lesser drug offenses to be involved in small-scale thefts and other types of crime. Overall, drug use and crime are mutually reinforcing facets of a deviant lifestyle. Drug law enforcement in Finland has a high priority among police, and it has been largely effective through questioning and circumstantial evidence. When compared to many other European countries, however, drug investigations by Finnish police are more reactive than proactive.