Lonergan has been regarded as a peerless interpreter of Thomas, no one has therefore questioned the adequacy of his Thomistic interpretations in his doctoral work on operative grace in Thomas. In this work, the author breaks new ground in questioning the accuracy of Lonergan's interpretations. Contents: Introduction. PART I: Thomas' Early Work, Thomas' Theory of the Human Will, A Text From the Early Thomas (Sentences). PART II: Thomas of the Middle Period (^BDe Veritae). PART III: Thomas in the Late Period. (Summa, De Malo). PART IV: Lonergan's Interpretation of Thomas, The Context of the Article, Internal Criticism, Argument from Silence, Doctrinal Implications. PART V: Lonergan and Justification, Luther's Teaching on Free Will, Calvin on Free Will, The Council of Trent and Human Freedom, Lonergan on Justification and Free Will, Conclusion. PART VI: The Investigation Widened, The First Influence, The Second Influence, The Fourth Influence: Activity and Passivity of the Will, Conclusion.