Police agencies can increase their effectiveness in the following ways: assign supplementary staff, including drug specialists, responsible for combatting drug problems; provide the necessary surveillance through increased manpower hours, technical resources, and camouflaged vehicles; allocate financial resources to employ informers; pay for observation points in local businesses; and make incriminating durg purchases. Agencies should understand the characteristics of drug underworld. Heroin addicts often turn to crime to pay for their increasing drug needs. They may become couriers and then eventually go into business on their own as minor traffickers who conceal small quantities of drugs in the body's natural cavities, conduct business at the contact point, but make delivery at a distant location. Most contacts are made in the evenings and on weekends -- those times when police officers are not normally at work. Officers should establish observation points in businesses or apartments near suspected contact points to observe the people involved in the drug traffic. Camouflaged vehicles and personal contacts can aid in supplementing this information. Large-scale raids are often ineffective because they provide too few leads on networks and too little evidence on offenses. Such information is gained more often through individual operations, which may be enhanced through the use of undercover agents who fake an interest in the drugs and then seize them and make arrests. Sample letters written by a heroin user are appended. Two footnotes are supplied.