The study analyzed charging, plea negotiation, and sentencing practices at three stages -- 1981, 1982, and 1984 -- in the evolution of the guidelines. Practices under the guidelines were, in turn, contrasted to preguideline data from 1978. Statewide data were used to examine general trends in case processing and sentencing practices. Data from eight counties were used to evaluate changes in the factors influencing charging, plea bargaining, and sentencing practices, and a questionnaire was distributed to prosecutors, judges, and public defenders in the same eight-county region. Findings show that, compared with preguideline practices, sentencing in Minnesota is more uniform, more predictable, and more socioeconomically neutral than it was before the guidelines. Also, violent offenders are more likely to be imprisoned now than before the guidelines. These changes were achieved without placing additional burdens on State correctional resources. The Minnesota guidelines have remained firm when threatened by the inevitable backlash from older policies and practices. The Minnesota guidelines thus constitute a milestone experiment in sentencing reform. 3 tables, 4 additional readings.