Book excerpt: The second edition retains the selection of texts presented in the first edition but offers them in new translations by Richard J Regan -- including that of his Aquinas, Treatise on Law (Hackett, 2000). A revised Introduction and glossary, an updated select bibliography, and the inclusion of summarising headnotes for each of the units -- Conscience, Law, Justice, Property, War and Killing, Obedience and Rebellion, and Practical Wisdom and Statecraft -- further enhance its usefulness.