The concept of restorative justice is based loosely on several related, though distinct, theoretical, religious, and historical traditions. Efforts to implement restorative justice policies in criminal processes in the United States have recently experienced a dramatic upsurge. However, the article notes, successful implementation and theory testing both require careful theoretical specification, something that restorative justice currently seems to lack. The article attempts to identify heretofore unaddressed theoretical problems and offers directions for researchers and practitioners to both ameliorate those problems and permit adequate testing and implementation. The article also describes current applications of restorative justice programs that may help clarify conceptual ambiguity. Restorative justice practices include victim-offender reconciliation programs, family group conferences, restorative sentencing, and circle sentencing. The article suggests the need for a sustained research program proceeding from agreed specifications that seeks rigorous answers to critical questions. Table, references