THE THEORETICAL AND EMPIRICAL UNDERPINNINGS OF DIVERSION IN CRIMINOLOGY ARE DISCUSSED, AND THE DEVELOPMENT OF THE DIVERSION ALTERNATIVE IS TRACED. APPLICATIONS OF DIVERSION TO SPECIFIC CATEGORIES OF OFFENSES--STATUS OFFENSES, MISDEMEANORS AND MINOR FELONIES, FELONIES--ARE NOTED. IT IS POINTED OUT THAT AN ACCURATE ASSESSMENT OF THE SUCCESS OR FAILURE OF THE DIVERSION CONCEPT IS DIFFICULT BECAUSE FUNDS FOR METHODOLOGICALLY SOUND EVALUATIONS GENERALLY HAVE NOT BEEN AVAILABLE. THE MAJOR THREAT TO THE CONTINUING EXISTENCE OF DIVERSION PROGRAMS IS SAID TO BE THE CONSERVATIVE TREND IN CRIMINAL JUSTICE--THE VIEW THAT REHABILITATION DOES NOT WORK. ANOTHER MAJOR PROBLEM HAS TO DO WITH THE LEGAL STATUS OF ACCUSED PERSONS WHO PARTICIPATE IN DIVERSIONARY PROGRAMS. EVALUATIVE DATA ARE PRESENTED FROM THE MIAMI TREATMENT ALTERNATIVES TO STREET CRIME (TASC) PROGRAM, ONE OF SEVERAL LEAA-FUNDED PROJECTS DESIGNED TO DIVERT DRUG-USING ARRESTEES INTO COMMUNITY TREATMENT AGENCIES. THE DATA PROVIDE A COMPARISON OF PROGRAM PARTICIPANTS AND OTHER DRUG USERS IN TERMS OF SOCIODEMOGRAPHIC AND SOCIOECONOMIC CHARACTERISTICS AND DRUG USE PATTERNS. THE MIAMI TASC PROGRAM FAILED TO ACHIEVE LOCAL SUPPORT AND WAS TERMINATED. A MAJOR FACTOR IN THE PROGRAM'S FAILURE WAS THAT MOST CLIENTS WERE RETURNED TO JAIL BY TREATMENT AGENCIES, WHOSE DIRECTORS APPARENTLY FELT THAT TASC CLIENTS WERE NOT AMENABLE TO TREATMENT. AS HAS BEEN THE CASE WITH OTHER DIVERSION PROGRAMS, THE MIAMI TASC PROGRAM GENERATED UNREALISTICALLY HIGH EXPECTATIONS OF WHAT IT COULD ACCOMPLISH, THUS RENDERING EVALUATIVE EFFORTS EXTREMELY DIFFICULT. SUPPORTING TABULAR DATA AND A LIST OF REFERENCES ARE INCLUDED. (LKM)