This study reviewed sentencing data for 1989 in four large district courts in the eighth circuit. This year was selected because approximately 60 percent of the sentences imposed were guidelines sentences. The eighth circuit data were supplemented with nationwide statistics generated by the Sentencing Commission for all 18-to 35-year-old male Federal offenders sentenced in 1989 by race, type of offense, and sentence length. The research indicates that the guidelines have had a significant role in increased Federal case filings, in longer sentences, and in the imposition of prison terms on offenders who previously would have received probation. Although one of the primary aims of the guidelines is to reduce sentencing disparity for similar offenses and similar offenders, this has not been achieved, largely because the guidelines have done nothing to curb discretion in the executive and legislative branches. Prosecutors have unparalleled power over sentencing issues, and this discretion is not subject to judicial review or public scrutiny. The study also concludes that guidelines enhancements criminalize and set the punishment for specific acts without affording the constitutional safeguards required for a criminal conviction. The recommendations offered are intended to mitigate these guidelines' unintended negative impacts. 11 tables and 28 footnotes