Source: (2003) Restorative Justice Online. September 2003 Edition.According to Gerry Johnstone, the international scope of the restorative justice movement and the diverse ideas and practices characterizing the movement create difficulties for individuals attempting to understand it. Since restorative justice is not a set of practices that grew out of single coherent theory but a paradigm of justice that grew out of practical experimentation with the theory growing as the practice grew, the underlying values and ideas are often hard to capture from the wide variety of material available. Johnstone states that "it is possible to read repetitive materials on a few aspects of restorative justice while never learning of other aspects." For this reason, he has worked to pull together a wide range of readings covering the restorative justice history and developments, theory and values, process and practices, and critical issues in a single volume, A Restorative Justice Reader: Texts, Sources, Contexts.