The types of constitutional clauses relevant to the legality of capital punishment are reviewed, followed by an examination of whether the death sentence is, under a constitution guaranteeing due process of law, per se unconstitutional, which would mean that it is unlawful in all circumstances for whatever offense and by whatever procedure it is imposed. The discussion also considers the contentions raised before the courts that the death penalty is invalid where it is imposed by a cruel method, where its imposition is in the discretion of the sentencing authority, where it is mandatory for a defined offense, where it is disproportionate to the capital offense, or where it is otherwise the result of caprice or other procedural irregularity. The debate on the compatibility of capital punishment and the equal protection of the laws is also reviewed. The relevance of executive clemency to the constitutionality of capital punishment is considered as well. The concluding judgment is that capital punishment imposes an unacceptable degree of mental and physical cruelty by whatever method it is performed, is discriminatorily applied against the poor and minorities, has no standards to distinguish the executed from the reprieved, and serves no valid penological purpose. Notes accompany each chapter, and a subject index is provided.