Evidence for the hypothesis of a causal link between unrepresentative juries and the commissioner selection method is derived from three ancillary propositions which the accumulated evidence supports: (1) that the socioeconomic characteristics of the commissioners are similar to the jurors they select and that a similar correspondence exists between the criminal court judges and the commissioners whom they appoint; (2) that commissioners tend overwhelmingly to appoint their personal friends, relatives, and associates to the jury panels and that most commissioners were personally acquainted with the appointing judge prior to the appointment; and (3) that a substantial portion of the commissioners have served more than once either as commissioners or as grand jurors. The second principal hypothesis of the study is that the time-consuming nature of grand jury service precludes a cross-section of the community from serving as grand jurors. Data to support these hypotheses came from a mailed questionnaire sent to all persons who served as commissioners between 1969 and 1974; interviews with past and present commissioners, criminal court judges, members of the district attorney's staff, State legislators, and lawyers, and miscellaneous reference sources. If grand juries are to be representative of the community, they should be randomly selected from a list of all persons in the jurisdiction who are eligible for jury service.