The perspicuity or clarity of Scripture in its relation to almost all areas of systematic theology is affected by postmodern hermeneutics that fail to respect the authority of Scripture. The doctrine raises a number of questions difficult to answer in a brief span, but two very basic issues are the meaning of the doctrine of perspicuity and the long-range historical context in which the doctrine has arisen. The basic doctrine means that the Bible can be understood by people through the enlightenment of the Holy Spirit and that people need to search the Scripture and judge for themselves what it means. Scripture itself attests its own perspicuity, but not to the point that it cannot be misunderstood or is in every point equally simple and clear. The doctrine does not rule out the need for interpretation, explanation, and exposition of the Bible by qualified leaders. The doctrine does mean that Scripture is clear enough for the simplest person, deep enough for highly qualified readers, clear in its essential matters, obscure in some places to people because of their sinfulness, understandable through ordinary means, understandable by an unsaved person on an external level, understandable in its significance by a saved person through the illumination of the Holy Spirit, and available to every believer whose faith must rest on the Scriptures. Historically, debates about perspicuity have related to Marcion’s attack on the OT, the fathers’ denial of OT perspicuity, covenant theology’s subordination of the OT to the NT, and the medieval church’s attack on biblical perspicuity. The Reformers, the Protestant scholastics, and theGerman pietists supported the doctrine which is of primary importance for the practice of contemporary Christians.