On Power (De Potentia) is one of Aquinas's ''Disputed Questions'' (a systematic series of discussions of specific theological topics). It is a text which anyone with a serious interest in Aquinas's thinking will need to read. There is, however, no English translation of the De Potentia currently in print. Fr. Richard Regan has produced this abridgement, which passes over some of the full text while retaining what seems most important when it comes to following the flow of Aquinas's thought.