It is pretty well agreed that Philipp Melanchthon's views on grace and free will developed or at least changed. There is less agreement on where and when the journey started and where it finished. Gregory Graybill does a good job in summarising this historical and theological debate, and in patiently developing his own account of the course of events, using Melanchthon's numerous writings and re-writings to do so. He is well-informed, mostly clear, and fair-minded. In a change from Luther's determinism that began about 1522 Melanchthon for many years espoused what might be called the two kingdoms view. Entry into the heavenly kingdom was via monergistic regeneration in which the will was freed from bondslavery to sin by an influx of divine grace. In the earthly kingdom, the will was free to decide this or that, to obey parents, to restrain from theft and murder and so on. This fitted neatly with Luther's political theology, but how these two kingdoms meshed in one consistent whole was not clear, and Melanchthon seems to have left that problem to the Almighty. This change, with an accompanying emphasis on the place of natural law and the importance of general education, was made for pastoral reasons, not least to counter the threat of civil disturbance, concern over the doctrine of predestination, and issues of personal assurance. 1532 was the tipping point, with yet another commentary on Romans. He begins to find a place for free will in justification via a kind of divine and human co-action. The changes were noticed. The author faithfully chronicles these – the Regensburg Colloquy, 1541, the Loci communes of 1543, and then of 1553. Yet another Romans commentary. Bit by bit the scope of free will was enlarged, the particularity of divine providence was diminished, predestination was almost unmentioned. The two-kingdoms doctrine became blurred. Fellow-Lutherans noticed the changes, there was controversy with such as Gallus. Calvin reproached his friend, first privately, then publicly. The crucial thing was the origin of faith; Melanchthon offered a third way, though by no means a clear way: God draws the willing. Yet, as Graybill says, this mare's nest (he does not call it that) remains a popular evangelical formulation. If there is a weakness in the book it is at the conceptual level. At the outset Graybill boldly makes a three-fold distinction between freedom in contingency, conversion and good works. There is need here for some background to aid the reader. Where did this distinction, which is not a usual one, come from? Whose was it? Graybill's persistent use of the term ‘determinism’ is surely anachronistic. In one of his brief treatments of the distinction between the necessity of the consequence and the necessity of the consequent there seems to be some confusion (pp. 74–5). But all in all this is an excellent narrative, informative and persuasive.