Among the constitutional rights guaranteed to criminal defendants by the 6th and 14th amendments is the right to compulsory process, which entitles defendants to call and present witnesses whose testimony is reliable and crucial to the defense. A review of the history of this right begins with the broad interpretation of the compulsory process clause in the 1806-07 treason and misdemeanor trials of Aaron Burr. The right was generally neglected until 1967 when the Supreme Court, in Washington v. Texas, expanded on the early interpretation by holding that the clause entitles the accused to call witnesses and to have those witnesses testify at trial, notwithstanding common law rules to the contrary. The Court also ruled that this right applies to the States through the 14th amendment as a fundamental element of due process of law. In Chambers v. Mississippi, this right was reaffirmed. Frye v. United States (1923) was the seminal case in a long line of decisions rejecting polygraph evidence; and under the standard adopted here, polygraphy would be admissible only if it had become generally accepted in the scientific community. Since then, the polygraph has evolved into a proven technique for detecting deception. The main objection of most courts today, that such evidence would amount to a subversion of the jury system, is not valid. If juries can evaluate other complex scientific evidence, they can also be expected to evaluate polygraph evidence. Related court cases are considered. Footnotes with references are included.