The interrogatory stage of police investigation is examined in terms of the jurisprudence of interrogation, common deceptive interrogation practices, and the ethics of police deception. Three sometimes conflicting principles underlie the law of confessions: the truth-finding rationale, the substantive due process or fairness rationale, and the related deterrence principle. The typology of interrogatory deception presented here discusses interview versus interrogation, Miranda warnings, misrepresentation of the nature or seriousness of the offense, role playing, misrepresentation of the moral seriousness of the offense, the use of promises, the misrepresentation of identity, and fabricated evidence. Police interrogatory deception can undermine public confidence and social cooperation and result in the conviction of innocent people. 62 notes