A brief history of the criminal justice system precedes a basic description of the system in terms of a flow chart. Following a series of eight basic definitions of fundamental judicial and correctional system processes, a conceptual model of the criminal justice system defines five major stages undergone by an individual as a result of involvement with the system: (1) crisis (arrest), (2) intervention (booking, detention, pretrial investigation, and standing trial), (3) corrective action (rehabilitation), (4) reentry (parole, halfway house assignment, etc.), and (5) community adjustment. A description of the drug abuse treatment system model also begins with a brief summary of major drug abuse laws dating from 1912 to 1978, and a discussion of the relative absence of drug abuse treatment programs from 1912 to 1960. The drug abuse treatment system is described in terms of three different models: the central intake model, the random intake model, and the generalist service model. A concluding conceptual model of the drug abuse treatment system also explains the phases of client movement in terms of crisis, intervention, corrective action, reentry, and community adjustment. It is concluded that use of this identical generic process for both systems can more easily determine points of interface and collaboration. Six diagrams of models and 12 references are provided.