The task of this article is a two-fold approach to Augustine’s theory of knowledge, often called that of ‘divine illumination’, with particular attention to one of its seminal sources, his Soliloquia. The first approach is historical- and text-critical; we consider the text of the Soliloquia, its meaning and significance, the questions to which Augustine was implicitly responding at the time, and especially how this work broaches themes which are revisited and further developed in Augustine’s later works. In the second part, (...) we take the results of the foregoing analysis and apply to them a systematic-theological and philosophical method. First we contextualize Augustine’s theory of illumination, both in relation to his own works and beyond. We then argue for a distinction between two senses of illumination, namely ‘principal’ and ‘gradual’, which helps to account for the different ways in which illumination is applied by Augustine. Finally, we show how Augustine’s insights can be relevant to contemporary philosophy and theology, and how his ideas are implicated in contemporary debates. The upshot is an historical, philosophical, and theological consideration of Augustine’s theory of divine illumination, which aspires to strike a balance between doing justice to the text from an historical perspective and interpreting and applying it in the present day. (shrink)