What is the natural law and why does Aquinas think that we ought to obey it? What is the relation between the natural law and the practical law of a particular country?

 “Summa Theologica” by Thomas Aquinas – Aquinas extensively discusses natural law and its

relation to divine law and human conduct in this seminal work of Christian theology.

 “On Law, Morality, and Politics” by Thomas Aquinas – This collection of Aquinas’ writings

includes discussions on natural law theory and its implications for ethics and governance.

 “Natural Law and Natural Rights” by John Finnis – Finnis provides a contemporary analysis

of natural law theory, drawing on Aquinas’ insights and addressing its relevance in modern

jurisprudence.

 “The Natural Law Tradition in Ethics” edited by John Dionysius Lennard – This anthology

offers a comprehensive overview of the natural law tradition, including Aquinas’ contributions

and its evolution over time.

 “Aquinas: A Beginner’s Guide” by Edward Feser – Feser provides an accessible introduction

to Aquinas’ philosophy, including his understanding of natural law and its significance in moral

reasoning and social order.