Stark theoretical and ideological differences abound regarding the purpose of punishment, the circumstances under which it can be imposed, and who holds the ultimate authority to impose it. Because these age-old debates are not likely to be resolved in the near future, should Congress decide to address the issue of federal sentencing again, it ought to begin its inquiry from a point of consensus. Are there "first principles" of punishment and sentencing on which most Americans can agree? What lessons have we learned from the last thirty years of sentencing reform and the past hundred years of criminal justice reform? One critical lesson has been that the connection between substance and procedure is quite formidable in virtually every aspect of criminal law. Procedural and substantive law ought to function together to create a justice system that is fair and reliable. Unfortunately, this lesson has gone virtually unheeded in the arena of criminal sentencing. The lack of attention to sentencing procedures has been one of the greatest failings of the last century's sentencing reform movement and is the cause of much of the current upheaval in federal sentencing. Any revisions to the federal sentencing scheme should attend to the procedural and evidentiary law of sentencing as painstakingly as prior reform efforts did to the substantive law of sentencing. Most notably, the inattention--whether by design or neglect--to basic procedural safeguards threatens one of our most fundamental components of due process: the adversarial system of justice...