This essay reviews some of the recent critical writings on medieval confession and discusses their importance to the ongoing debates about the history and formation of the self as subject. Building on the evidence that the rise of annual, required confession led to the emergence of “confessional literature” (works using the tropes and methods of the confessional to structure narrative), the essay suggests that the ways of understanding the self made available through such works form a kind of “vernacular psychology”– that is, a practical, quotidian alternative to Aristotelian/philosophical or Galenic/medical modes of thinking about the self. “Vernacular psychology” describes this widespread set of medieval understandings of the self that were made public in a range of writings in English and Anglo-Norman (only the former is considered here). Such understandings stressed the self's vulnerability to sin, conceived as something that both attacks the self from without and is generated from within, implying a range of relations between the “self” and the “world” that the large array of Middle English “confessional” writings offer in distinction to the Latin clerical tradition.