Diversion from the formal criminal justice process has always been a part of the administration of justice in the United States, but recently it has become formalized, organized, and integrated with all levels of the criminal justice system; there are now more than 100 formal diversion programs throughout the country. Increasingly, municipalities and States are instituting local diversion programs. Within the context of the programs' increasingly important role in the evolving legal system, this essay focuses on: (1) development of diversion alternatives; (2) theoretical and empirical underpinnings of diversion in criminology; (3) application of diversion to various types of offenses; and (4) an assessment of diversion. Diversion programs, such as the now defunct Treatment Alternatives to Street Crime, often generate unrealistically high expectations of what they will accomplish, thus making evaluative efforts more difficult. In addition, there is no funding to undertake methodologically sound assessment. The future of diversion programs is uncertain and the existence of diversion programs will depend on their ability to convince the legal system that they have an impact on their clients, do reduce criminal behavior, and will protect the community at least as well as prisons. Tables, references