On the Power of God is a set of disputed questions written around 1265–1266, towards the beginning of Thomas Aquinas’s time in Rome and just prior to the composition of the Prima Pars of the Summa theologiae. “Disputed questions” are considerably edited reports of school debates, or disputationes, on various questions or topics, in which supporting and opposing arguments on a given theme were discussed and then resolved by the presiding master. The disputed questions in this volume, On the Power of God, take their title from the first question but are more loosely unified; qq. 1–6 are on the topic of the power of God, but qq. 7–10 deal more proximately with Trinitarian theology.