This works is an interdisciplinary study that applies contemporary literary-critical theories of character and characterization to the study of the Holy Spirit in Luke-Acts After surveying various theories of how character functions in texts and between text and reader, the author identifies the Holy Spirit as a 'character' in Luke-Acts. By rhetorically becoming a character, the Holy Spirit functions to insure the reliability of Luke's proclamation and thus indirectly the reliability of God's promises. This work will be of interest to scholars and graduate students interested in the literary-critical analysis of scripture, Luke-Acts, and the Holy Spirit.