The positivist philosophies of the late 19th century and the first six decades of the 20th century ushered in the era of indeterminate sentences in the United States. Indeterminate sentences require that the length of the sentence served by an offender be dependent upon the rate at which the offender is rehabilitated while under the state's jurisdiction. Indeterminate sentencing was undermined by the discovery that rehabilitation programs rarely worked and that offenders were arbitrarily subjected to varying sentence lengths without regard to crime severity. Determinate sentencing, which fixes a sentence in accordance with crime severity and offender culpability, was introduced in the United States through sentencing guidelines systems epitomized in the current Minnesota and Pennsylvania sentencing systems. Canada currently operates under the indeterminate sentencing philosophy, but the guidelines given to the newly appointed Canadian Sentencing Commission by the Federal Order-in-Council make it clear that the commission is to develop determinate sentencing guidelines similar to Minnesota's. A major factor to be considered under such a system is the shift of sentencing discretion from the judge to the prosecutor in the context of plea negotiations. An appended description of Minnesota's sentencing guidelines calculations. 21 footnotes.