Investigation of clandestine drug manufacturing laboratories is a high priority of the U.S. Drug Enforcement Administration (DEA) because elimination of these laboratories will prevent drugs of abuse from reaching the illicit drug traffic. One of the important responsibilities of forensic chemists assisting investigations of clandestine drug laboratories is to be familiar with the methods of synthesis being used by clandestine laboratory operators. A review of clandestine laboratory seizures during the period of 1978 through 1981 will be provided to familiarize forensic chemists with current information on the types of laboratories being seized in the United States and the methods of synthesis being used. (Author abstract)