This dissertation is a study of the unity of Scripture's senses in Origen's exegesis. Scripture's revelation is the hiddenness of its spirit; the spiritual sense thus creates the possibility of the letter and its signification. Particularly in Peri Archôn 4, Origen proposes a method of interpretation which will allow the exegete to perceive Scripture's composition as an irreducible mystery.Chapter 1 establishes that the letter both reveals and constitutes the fullness of Scripture's meaning; the union of letter and spirit is perceived as the text's self-effacement. Chapter 2 then considers Origen's polemics against Jewish, heretical, and simplistic Christian literalisms as three kinds of reading which isolate the scriptural letter. Chapter 3 studies Origen's spiritual exegesis as a hermeneutic of the incarnation through a contextualized analysis of Peri Archôn 4.1 and 4.2. Scripture is powerful and efficacious because its form is the demonstration of its spirit. Origen further specifies the precise nature of this demonstration in the analogy Origen creates between Scripture and providence, in which both text and matter are the revelation of self-emptying love. Finally, by identifying the unspeakable mystery of the Word's incarnation with the unspeakable character of wisdom revealed in the scriptural letter, we perceive the intrinsic hiddenness of Scripture's meaning. Chapter 4 gathers Origen's major discussions of transfiguration, drawing implications both for the scriptural text and for the conformation to Christ necessary for the exegete to perceive the letter transfigured.Origen's spiritual exegesis resists the reduction of Scripture to a dichotomy of senses. Such a dichotomy is unable to account for the mystery of God's self-revelation. Scripture's letter, for Origen, is neither the representation of the spiritual sense nor accidental to it, but the form and image of an unspeakable mystery.