Data were collected on the total number of criminal homicides in all States following the 1972 Furman decision striking down State death penalty statutes that allowed arbitrary and discriminatory imposition of the death sentence. Statistics on the death sentences handed down and appellate review of those sentences in States selected for review since the Furman decision and the criminal processing of potental capital cases from charge through sentencing in one of the States were also gathered and analyzed. Probabilities were constructed to determine the likelihood of receiving the death sentence by race of the victim and the defendant, jurisdiction, stage of process where sentence was imposed or finally upheld, classification of the crime as felony or nonfelony homicide, circumstances of the crime as reported by the police and by structure of the death penalty law itself as providing for quasi-mandatory or nonmandatory imposition of the sentence for specific crimes. The findings show gross differences in the treatment of potentially capital offenders by race of offender and victim and by judicial circuits within States. These findings are independent of aggravating felony-related circumstances, present at both presentencing and sentencing stages of the criminal justice process, uncorrected by postsentence appellate review processes, unaltered by the form and restrictiveness of capital statutes among States, and similar to the best documented patterns of differential treatment by race of offender and victim under pre-Furman capital statutes. The findings show that the present system of capital punishment is inconsistent with the constitutional standards of the Furman and Gregg decisions of the U.S. Supreme Court. The system is instead consistent with historically prevailing extralegal influences which compromise and displace the legally prescribed functions of such punishment and are an enduring source of arbitrariness and discrimination. Footnotes and data tables are included. Data adjustment procedures and a list of data sources are appended. (Author abstract modified)