The best biography for becoming familiar with St. Thomas's life and works in their historical setting is:

Weisheipl, James, OP. Friar Thomas d’Aquino: His Life, Thought, and Work. New York: Doubleday, 1974.

This book is a little dated when it comes to more technical details, like the dating of Aquinas's works. For the best biography in terms of the dating of Aquinas's works, see:

Torrell, Jean Pierre, OP. Saint Thomas Aquinas: The Person and His Work. 3rd ed. Washington, DC: The Catholic University of America Press, 2023.

Torrell's biography contains a comprehensive timeline of Aquinas's life and works and an appendix describing the best available editions. This appendix is significantly revised in the 3rd edition. Some other recent, scholarly bibliographies of Aquinas:

Porro, Pasquale. Thomas Aquinas: A Historical and Philosophical Profile. Translated by Joseph Trabbic and Roger Nutt. Washington, DC: The Catholic University of America Press, 2016. [Originally Italian version 2012.]

Prudlo, Donald. Thomas Aquinas: A Historical, Theological, and Environmental Portrait. New York: Paulist Press, 2020.

For more popular biographies of St. Thomas, there is G. K. Chesterton's The Dumb Ox [St. Thomas Aquinas] and Joseph Pieper's Guide to Thomas Aquinas and Silence of St. Thomas (especially ch. 1). One should read all three of these with a grain of salt, however. The information in them is very dated and sometimes over dramatized.

Companions

Stump, Eleonore and Thomas Joseph White, OP, eds. The New Cambridge Companion to Aquinas. Cambridge: Cambridge University Press, 2002.

Kretzmann, Norman and Eleonore Stump, eds. The Cambridge Companion to Aquinas. Cambridge: Cambridge University Press, 1993.

Davies, Brian and Eleonore Stump, eds. The Oxford Handbook of Aquinas. Oxford: Oxford Unviersity Press, 2014.

Levering, Matthew and Marcus Plested, eds. The Oxford Handbook of the Reception of Aquinas. Oxford: Oxford University Press, 2021.

General Introductions to His Whole Thought

Brock, Stephen. The Philosophy of Saint Thomas Aquinas: A Sketch. Eugene, OR: Cascade Books, 2015.

Copleston, Frederick, SJ. Aquinas: An Introduction to the Life and Work of the Great Medieval Thinker. London: Penguin, 1955.

Feser, Edward. Aquinas: A Beginner's Guide. Oxford: Oneworld Publications, 2009.

Garrigou-Lagrange, Reginald. Reality: A Synthesis Of Thomistic Thought. St. Louis: Herder, 1950.

Gilson, Étienne. Thomism: The Philosophy of Thomas Aquinas. Translated by Laurence Shook and Armand Maurer. 6th ed. Toronto: Pontifical Institute of Mediaeval Studies, 2002.

McInerny, Ralph. First Glance At Thomas Aquinas: A Handbook for Peeping Thomists. Notre Dame: University of Notre Dame Press, 1989.

Shields, Christopher, and Robert Pasnau. The Philosophy of Aquinas. 2nd ed. Oxford: Oxford University Press, 2016.

Stump, Eleonore. Aquinas. London: Routledge, 2005.

Del Prado, Norbert, OP. De veritate fundamentali philosophiae Christianae. Friburgi: Ex typis Consociationis Sancti Pauli, 1911.

Gredt, Joseph, OSB. Elementa philosophiae Aristotelico Thomisticae. 2 vols. 11th ed. Friburg: Herder, 1961.

Hugon, Eduardo, OP. Cursus philosophiae Thomisticae ad theologiam Doctoris Angelici propaedeuticus. 3 vols. Paris: Sumptibus P. Lethielleux, 1927.

John of St. Thomas, OP (Poinsot). Cursus philosophicus Thomisticus. Edited by Beatus Reiser. 3 vols. Hildesheim: Georg Olms, 2008.

Liguori, Alphonsus, CSsR. Theologia moralis. 2 vols. Turin: Marietti, 1891.

Maquart, F.-X. Elementa philoosphiae seu brevis philosophiae speculativae synthesis ad studium theologiae manuducens. 4 vols. Paris: Andreas Blot, 1937–1938.

Mercier, Desiré. A Manual of Modern Scholastic Philosophy. 3rd English ed. 2 vols. London: Kegan Paul, Trench, Trubner, 1926.

Prümmer, Dominic, OP. Handbook of Moral Theology. Translated by Gerald Shelton. 2 vols. Cork: The Mercier Press, 1956.

* For Aquinas, like other medieval thinkers, the liberal arts are a set of intellectual habits that everyone needs before studying philosophy or theology. Thus, it is a good idea to give yourself at least some basis in these before trying to read his original writings or even secondary literature about him. It will make a lot more sense!

1. Logic Textbooks

Ashley, Benedict, OP. The Arts of Learning and Communication: A Handbook of the Liberal Arts. Dubuque: The Priory Pre ss, 1958. [This high school textbook is remarkable for its breadth and clarity. It efficiently covers not only the basics of Aristotelian logic, but also the basics of the Aristotelian theory of poetry and rhetoric and basic natural philosophy.]

Houser, Rollen Edward. Logic as a Liberal Art: An Introduction to Rhetoric and Reasoning. Washington, DC: The Catholic University of America Press, 2020.

John of St. Thomas, OP (Poinsot). Material Logic. Translated by Yves Simon and John Granville. Chicago: University of Chicago Press, 1955. [This is an advance seventeenth-century textbook, which was very popular among mid-twentieth-century Thomists.]

John of St. Thomas, OP (Poinsot). Outlines of Formal Logic. Translated by Francis Wade. Milwaukee, WI: Marquette University Press, 1962.

Kreeft, Peter. Socratic Logic: A Logic Text using Socratic Method, Platonic Questions, and Aristotelian Principles. Edited by Trent Dougherty. 3rd ed. South Bend, IN: St. Augustine's Press, 2010. [This book is unique for its focus on informal reasoning and reasoning in ordinary language.]

Oesterle, John. Logic: The Art of Defining and Reasoning. Englewood Cliffs, NJ: Prentice-Hall, 1963. [This is probably the most used twentieth-century undergraduate textbook on logic.]

2. Logic Monographs / Important Articles

Ashworth, E. J. “Signification and Modes of Signifying in Thirteenth-Century Logic: A Preface to Aquinas on Analogy.” Medieval Philosophy & Theology 1 (1991): 39–67.

Ashworth, E. J. “Analogy and Equivocation in Thirteenth-Century Logic: Aquinas in Context.” Mediaeval Studies 54 (1992): 94–135.

Klima, Gyula. “The Semantic Principles Underlying Saint Thomas Aquinas’s Metaphysics of Being.” Medieval Philosophy and Theology 5 (1996): 87–141.

McInerny, Ralph. The Logic of Analogy: An Interpretation of St Thomas. The Hague: Martinus Nijhoff, 1971.

Schmidt, Robert. The Domain of Logic according to Saint Thomas Aquinas. The Hague: Martinus Nijhoff, 1966.

Veatch, Henry. Intentional Logic: A Logic Based on Philosophical Realism. New Haven, CT: Yale University Press, 1952. [This is a detailed and systematic exposition of Veatch's Thomistic theory of logic, heavily influenced by John of St. Thomas.]

Veatch, Henry. Two Logics: The Conflict between Classical and Neo-Analytic Philosophy. Evanston, IL: Northwestern University Press, 1969. Reprint ed., Heusenstamm: Editiones Scholasticae, 2019. [This is a polemical comparison of Aquinas and Aristotle's so-called "what"-logic, based on definitions and per se propositions, with the "relational"-logic of Bertrand Russell, based on logical consequences.]

Lonergan, Bernard, SJ. Insight. Collected Works of Bernard Lonergan 3. Toronto: University of Toronto Press, 1992.

Maritain, Jacques. The Degrees of Knowledge [Distinguish to Unite]. Collected Works of Jacques Maritain 7. Notre Dame: University of Notre Dame Press, 1995.

Gilson, Etienne. Thomist Realism and The Critique of Knowledge. Translated by Mark Wauck. San Francisco: Ignatius Press, 2012.

Owens, Joseph, CSsR. Cognition: An Epistemological Inquiry. Notre Dame: University of Notre Dame Press, 1992.

Van Steenberghen, Fernand. Epistemology. Translated by Martin Flynn. New York: Joseph Wagner, 1949.

Rahner, Karl, SJ. Spirit in the World. Translated by William Dych. New York: Continuum, 1994.

1. Textbooks / General Overviews

Feser, Edward. Aristotle's Revenge: The Metaphysical Foundations of Physical and Biological Science. Neunkirchen-Seelscheid: Editiones Scholasticae, 2019.

Smith, Vincent Edward. Philosophical Physics. New York: Harper & Bros., 1950.

Wallace, William, OP. The Modeling of Nature: Philosophy of Science and Philosophy of Nature in Synthesis. Washington, D.C.: Catholic University of America Press, 1996.

2. Monographs 

Crowley, Charles Bonaventure, OP. Aristotelian-Thomistic Philosophy of Measure and the International System of Unites (SI): Correlation of the International System of Units with the Philosophy of Aristotle and St. Thomas Aquinas. Edited by Peter Redpath. Lanham: University Press of America, 1996.

Koons, Robert. Is St. Thomas’s Aristotelian Philosophy of Nature Obsolete? South Bend: St. Augustines Press, 2022.

Shields, Daniel. Nature and Nature’s God: A Philosophical and Scientific Defense of Aquinas’s Unmoved Mover Argument. Washington, DC: The Catholic University of America Press, 2023.

Simon, Yves. The Great Dialogue of Nature and Space. Edited by Gerard Dalcourt. Albany: Magi Books, 1970.

3. Important Articles

Decaen, Christopher. “Aristotle’s Aether and Contemporary Science.” The Thomist 68, no. 3 (2004): 375–429.

Decaen, Christopher. “Elemental Virtual Presence in St. Thomas.” The Thomist 64, no. 2 (2000): 271–300.

Decaen, Christopher. “An Inductive Study of Equivocal Causality in St. Thomas.” The Thomist 79, no. 2 (2015): 213–63.

McLaughlin, Thomas. “Aristotelian Mover-Causality and the Principle of Inertia.” International Philosophical Quarterly 38, no. 150 (1998): 137–51.

McLaughlin, Thomas. “Aristotelian Definition of Motion and the Principle of Inertia.” PhD diss., University of St. Thomas (TX), 2001.

McLaughlin, Thomas. “Local Motion and the Principle of Inertia: Aquinas, Newtonian Physics, and Relativity.” International Philosophical Quarterly 44, no. 174 (2004): 239–64.

McLaughlin, Thomas. “Nature and Inertia.” The Review of Metaphysics 62 (2008): 251–84.

McLaughlin, Thomas. “Act, Potency, and Energy.” The Thomist 75, no. 2 (2011): 207–42.

McLaughlin, Thomas. “A Defense of Natural Place in a Contemporary Scientific Context.” Proceedings of the American Catholic Philosophical Association 93 (2019): 101–15.

Wallace, William, OP. “Saint Thomas and the Pull of Gravity.” In Science and the Liberal Concept, 143–65. West Hartford, CT: St. Joseph College, 1964.

4. Essay Collections

Wallace, William, OP. Intelligibility of Nature: A William A. Wallace Reader. Edited by John Hittinger, Michael W. Tkacz, and Daniel Wagner. Washington, DC: The Catholic University of America Press, 2023.

Weisheipl, James, OP. Nature and Motion in the Middle Ages. Edited by William E. Carroll. Washington, DC: The Catholic University of America Press, 1985.

5. History of Natural Philosophy from Thomistic Perspective

Wallace, William, OP. Causality and Scientific Explanations: Medieval and Early Classical Science. 2 vols. Ann Arbor: The University of Michigan Press, 1972–1974.

1. Introductory Textbooks

Augros, Michael. The Immortal in You: How Human Nature Is More Than Science Can Say. San Francisco: Ignatius Press, 2006.

Jensen, Steven. The Human Person: A Beginner's Thomistic Psychology. Washington, DC: The Catholic University of America Press, 2018.

Madden, James. Mind, Matter, and Nature: A Thomistic Proposal for the Philosophy of Mind. Washington, DC: The Catholic University of America Press, 2013.

Vonier, Anscar, OSB. The Human Soul. San Francisco: Ignatius Press, 2010.

2. Advanced Studies of Human Nature

Pasnau, Robert. Thomas Aquinas on Human Nature: A Philosophical Study of Summa Theologiae 1a 75–89. New York: Cambridge University Press, 2004.

3. Advanced Studies of Human Cognition

Geach, Peter. Mental Acts: Their Content and Their Object. London: Routledge & Kegan Paul, 1957.

Kenny, Anthony. Aquinas on Mind. London: Routledge, 1993.

Lonergan, Bernard, SJ. Verbum: Word and Idea in Aquinas. Collected Works of Bernard Lonergan 2. Toronto: University of Toronto Press, 1997.

Owens, Joseph, CSsR. Cognition: An Epistemological Inquiry. Houston, TX: Center for Thomistic Studies, 1992.

Madden, James. Thinking about Thinking: Mind and Meaning in the Era of Techno-Nihilism. Cascade Books, 2023.

Pasnau, Robert. Theories of Cognition in the Later Middle Ages. Cambridge: Cambridge University Press, 1997.

Peifer, John Frederick. The Concept in Thomism. New York: Bookman Associates, 1952.

4. Evolution and Human Origins

Austriaco, Nicanor Pier Giorgio, OP, James Brent, OP, Thomas Davenport, OP, and John Baptist Ku, OP. Thomistic Evolution: A Catholic Approach to Understanding Evolution in the Light of Faith. Washington, DC: Cluny, 2016.

Austriaco, Nicanor Pier Giorgio, OP. “Defending Adam After Darwin: On the Origin of Sapiens as a Natural Kind.” American Catholic Philosophical Quarterly 92, no. 2 (2018): 337–52.

Chaberek, Michael, OP. Catholicism and Evolution: A History from Darwin to Pope Francis. Brooklyn, NY: Angelico Press, 2015.

Chaberek, Michael, OP. Knowledge and Evolution: How Theology, Philosophy, and Science Converge in the Question of Origins. Resource Publications, 2021.

Deely, John, and Raymond Nogar, eds. The Problem of Evolution: A Study of the Philosophical Repercussions of Evolutionary Science. New York: Appleton-Century-Crofts, 1973.

Kemp, Kenneth. The War That Never Was: Evolution and Christian Theology. Cascade Books, 2020.

Tabaczek, Mariusz, OP. Theistic Evolution: A Contemporary Aristotelian-Thomistic Perspective. Cambridge: Cambridge University Press, 2023.

What Thomistic metaphysics looks like will vary a lot depending on the school of Thomism in which it is found. For this reason, I've divided up this section by the various principal schools of Thomism. For more on these schools, click here.

1. Analytic Thomism

Feser, Edward. Scholastic Metaphysics: A Contemporary Introduction. Heusenstamm: Editiones Scholasticae, 2014.

Geach, Peter. “Aquinas.” In Three Philosophers, 65–125. Ithaca, NY: Cornell University Press, 1961.

Geach, Peter. God and the Soul. 2nd ed. South Bend, IN: St. Augustine’s Press, 1969.

Oderberg, David. Real Essentialism. New York: Routledge, 2007.

Stump, Eleonore. Aquinas. Arguments of the Philosophers. New York: Routledge, 2003.

2. Aristotelian Thomism [Broadly Construed]

Ashley, Benedict, OP. The Way Toward Wisdom: An Interdisciplinary and Intercultural Introduction to Metaphysics. Notre Dame: University of Notre Dame Press, 2006.

Dewan, Lawrence, OP. Form and Being: Studies in Thomistic Metaphysics. Studies in Philosophy and the History of Philosophy 45. Washington, D.C.: The Catholic University of America Press, 2006. [This collection of essays is not technically an introduction to metaphysics, but Dewan is an excellent guide to Aquinas's metaphysical thought even if this book, as an anthology, is less than comprehensive for Thomistic metaphysics.]

McInerny, Ralph. Praeambula Fidei: Thomism and the God of the Philosophers. Washington, DC: The Catholic University of America Press, 2006. [This polemical work is not technically an introduction to metaphysics and presupposes some prior knowledge of Aristotelian metaphysics, but it is arguably a better place to start than most metaphysics textbooks.]

McInerny, Ralph. Boethius and Aquinas. Washington, DC: Catholic University of America Press, 1990. [Again, this work is not technically an overview of Thomistic metaphysics, but it is very good for getting a less-than-comprehensive overview of some of the principal topics within metaphysics.]

White, Thomas Joseph, OP. Wisdom in the Face of Modernity: A Study in Thomistic Natural Theology. 2nd ed. Faith and Reason: Studies in Catholic Theology and Philosophy. Ave Maria, FL: Sapientia Press, 2016.

3. Existential Thomism [Broadly Construed]

Clarke, W. Norris, SJ. The One and the Many: A Contemporary Thomistic Metaphysics. Notre Dame: University of Notre Dame Press, 2001.

Owens, Joseph, CSsR. An Elementary Christian Metaphysics. Houston, TX: Center for Thomistic Studies, 1985. [This is a great textbook for Thomistic metaphysics in terms of its scope and lengthy footnotes. Readers should be aware, however, that Owens's particular interpretation of Aquinas is highly idiosyncratic. Even for readers who don't share Owens's reading of Aquinas, this book is a remarkable aid for studying his thought.]

Owens, Joseph, CSsR. The Doctrine of Being in the Aristotelian Metaphysics: A Study in the Greek Background of Mediaeval Thought. 3rd ed. Toronto: Pontifical Institute for Mediaeval Studies, 1978.

Maritain, Jacques. A Preface to Metaphysics. New York: Sheed & Ward, 1948.

Wippel, John. The Metaphysical Thought of Thomas Aquinas: From Finite Being to Uncreated Being. Washington, DC: The Catholic University of America Press, 2000. [This is the standard textbook of Thomistic metaphysics. It is definitely for a more advanced readership—late undergrads or grad students—not beginners. It is incomparable in its breadth and detailed engagement with both primary and secondary literature.]

4. Other

Van Steenberghen, Fernand. Ontology. Translated by Martin Flynn. New York: Joseph Wagner, 1952.

Mitchell, Jason. “Being and Participation: The Method and Structure of Metaphysical Reflection According to Cornelio Fabro.” PhD diss., Ateneo Pontificio Regina Apostolorum, 2012. [This enormous dissertation is a magisterial survey of the metaphysical thought of Cornelio Fabro, one of the most prominent Thomists of the twentieth century. Since his works are mostly in Italian or French, the dissertation is a major contribution to Thomistic philosophy in the English-speaking world.]

Medieval Exegesis in General (with Discussion of Aquinas)

De Lubac, Henri. Medieval Exegesis: The Four Senses of Scripture. 3 vols. Ressourcement: Retrieval and Renewal in Catholic Thought. Grand Rapids, MI: Eerdmans, 1998.

• vol. 1. Translated by Mark Sebanc.

• vol. 2. Translated by Ed Macierowski.

• vol. 3. Translated by Ed Macierowski.

Levy, Ian Christopher. Introducing Medieval Biblical Interpretation: The Senses of Scripture in Premodern Exegesis. Grand Rapids, MI: Baker Academic, 2018.

Levy, Ian Christopher. Holy Scripture and the Quest for Authority at the End of the Middle Ages. Notre Dame: University of Notre Dame Press, 2012.

Smalley, Beryl. The Study of the Bible in the Middle Ages. Notre Dame: University of Notre Dame Press, 1989.

St. Thomas on Scripture

Boyle, John. Aquinas on Scripture: A Primer. Steubenville, OH: Emmaus Academic, 2023.

Weinandy, Thomas G., OFM Cap., Daniel A. Keating, and John P. Yocum, eds. Aquinas on Scripture: An Introduction to His Biblical Commentaries. London: T&T Clark, 2005.

Valkenberg, Wilhelmus G. B. M. Words of the Living God: Place and Function of Holy Scripture in the Theology of St. Thomas Aquinas. Publications of the Thomas Instituut Te Utrecht 6. Leuven: Peeters, 2000.

Emery, Gilles, OP, and Matthew Levering, eds. The Oxford Handbook of the Trinity. Oxford: Oxford University Press, 2011.

Emery, Gilles, OP. The Trinitarian Theology of St. Thomas Aquinas. Translated by Francesca Murphy. Oxford: Oxford University Press, 2007.

Emery, Gilles, OP. The Trinity: An Introduction to Catholic Doctrine on the Triune God. Translated by Matthew Levering. Washington, DC: The Catholic University of America Press, 2011.

Lonergan, Bernard, SJ. The Triune God: Doctrines. Collected Works of Bernard Lonergan 10. Toronto: University of Toronto Press, 2007.

Lonergan, Bernard, SJ. The Triune God: Systematics. Collected Works of Bernard Lonergan 11. Toronto: University of Toronto Press, 2009.

White, Thomas Joseph, OP. The Trinity: On the Nature and Mystery of the One God. Thomistic Ressourcement Series. Washington, DC: The Catholic University of America Press, 2022.

Cross, Richard. The Metaphysics of the Incarnation: Thomas Aquinas to Duns Scotus. Oxford: Oxford University Press, 2002.

Gorman, Michael. Aquinas on the Metaphysics of the Hypostatic Union. Cambridge: Cambridge University Press, 2017.

Levering, Matthew. Reconfiguring Thomistic Christology. Cambridge: Cambridge University Press, 2023.

Lonergan, Bernard, SJ. The Incarnate Word. Collected Works of Bernard Lonergan 8. Toronto: University of Toronto Press, 2016.

Lonergan, Bernard, SJ. The Ontological and Psychological Constitution of Christ. Collected Works of Bernard Lonergan 7. Toronto: University of Toronto Press, 2002.

Pawl, Timothy. In Defense of Conciliar Christology: A Philosophical Essay. Oxford Studies in Analytic Theology. Oxford: Oxford University Press, 2016.

Pawl, Timothy. In Defense of Extended Conciliar Christology: A Philosophical Essay. Oxford Studies in Analytic Theology. Oxford: Oxford University Press, 2019.

West, J. L. A. Thomas Aquinas’ Use of Metaphysics: Natura, Suppostium and Esse. PhD diss., University of Waterloo, 2003.

White, Thomas Joseph, OP. The Incarnate Lord: A Thomistic Study in Christology. Thomistic Ressourcement Series. Washington, DC: The Catholic University of America Press, 2017.

Aumann, Jordan, OP. Spiritual Theology. 1980; repr., London: Continuum, 2006.

Garrigou-Lagrange, Réginald, OP. The Three Ages of the Interior Life. 2 vols. Translated by Sr. M. Timothea Doyle, OP. St. Louis, MO: Herder, 1947–1948.

Murray, Paul, OP. Aquinas at Prayer: The Bible, Mysticism and Poetry. London: Bloomsbury, 2013.

Torrell, Jean-Pierre, OP. Saint Thomas Aquinas. Vol. 2, Spiritual Master. Translated by Robert Royal. Washington, DC: The Catholic University of America Press, 2003.

Jensen, Steven. Living the Good Life: A Beginner's Thomistic Ethics. Washington, DC: The Catholic University of America Press, 2013.

McInerny, Ralph. Ethica Thomistica: The Moral Philosophy of Thomas Aquinas. Rev. ed. Washington, DC: The Catholic University of America Press, 1997.

Maritain, Jacques. Moral Philosophy: An Historical and Critical Survey of the Great Systems. New York: Charles Scribner's Sons, 1964.

Pinckaers, Servais, OP. Morality: The Catholic View. Translated by Michael Sherwin. South Bend, IN: St. Augustine's Press, 2001.

Pinckaers, Servais, OP. The Sources of Christian Ethics. Translated by Mary Thomas Noble. Washington, DC: The Catholic University of America Press, 2005.

MacIntyre, Alastair. After Virtue: A Study in Moral Theory. 3rd ed. Notre Dame: University of Notre Dame Press, 2007.

Anscombe, G. E. M. Intention. Cambridge, MA: Harvard University Press, 2000.

Brock, Stephen. Action and Conduct: Thomas Aquinas and the Theory of Action. Washington, DC: The Catholic University of America Press, 2021.

Hoffmann, Tobias. Free Will and the Rebel Angels in Medieval Philosophy. Cambridge: Cambridge University Press, 2022.

Jensen, Steven. Good and Evil Actions: A Journey through Saint Thomas Aquinas. Washington, DC: The Catholic University of America Press, 2010.

Jensen, Steven. Sin: A Thomistic Psychology. Washington, DC: The Catholic University of America Press, 2018.

Osborne, Thomas. Human Action in Thomas Aquinas, John Duns Scotus, and William of Ockham. Washington, DC: The Catholic University of America Press, 2014.

Pilsner, Joseph, CSB. The Specification of Human Actions in St Thomas Aquinas. Oxford: Oxford University Press, 2006.

Sherwin, Michael, OP. By Knowledge and By Love: Charity and Knowledge in the Moral Theology of St. Thomas Aquinas. Washington, DC: The Catholic University of America Press, 2011.

Brock, Stephen. The Light That Binds: A Study in Thomas Aquinas's Metaphysics of Natural Law. Eugene, OR: Pickwick, 2020.

Finnis, John. Natural Law and Natural Rights. 2nd ed. Oxford: Oxford University Press, 2011.

Hittinger, F. Russell. A Critique of the New Natural Law Theory. Notre Dame: University of Notre Dame Press, 1988.

Hittinger, F. Russell. The First Grace: Rediscovering the Natural Law in a Post-Christian World. Washington, DC: Intercollegiate Studies Institute, 2003.

Jensen, Steven. Knowing the Natural Law: From Precepts and Inclinations to Deriving Oughts. Washington, DC: The Catholic University of America Press, 2015.

Popović, Petar. Natural Law and Thomistic Juridical Realism: Prospects for a Dialogue with Contemporary Legal Theory. With foreword by F. Russell Hittinger. Washington, DC: The Catholic University of America Press, 2022.

Porter, Jean. Natural and Divine Law: Reclaiming the Tradition for Christian Ethics. Grand Rapids: Eerdmans, 1999.

Porter, Jean. Nature as Reason: A Thomistic Theory of the Natural Law. Grand Rapids: Eerdmans, 2004.

Rhonheimer, Martin. Natural Law and Practical Reason: A Thomist View of Moral Autonomy. New York: Fordham University Press, 1993.

Crean, Thomas, OP, and Alan Fimister. Integralism: A Manual of Political Philosophy. Heusenstamm: Editiones Scholasticae, 2020.

De Koninck, Charles. The Writings of Charles De Koninck. Translated and edited by Ralph McInerny. Vol. 2. Notre Dame: University of Notre Dame Press, 2009. [This contains his famous essays "The Primacy of the Common Good" and "The Principle of the New Order" as well as the responses from Simon and I. T. Eschmann and De Koninck's replies.]

Maritain, Jacques. The Person and the Common Good. Translated by John Fitzgerald. Notre Dame: University of Notre Dame Press, 1966.

Maritain, Jacques. Integral Humanism, Freedom in the Modern World, and A Letter on Independence. Collected Works of Jacques Maritain 11. Notre Dame: University of Notre Dame Press, 1996. [This controversial proposal for a new, secular Christendom, inspired by the thought of St.Thomas and written by arguably the most famous Thomists of the twentieth century, was wildly influential on Catholic political and ecclesial activity in the twentieth century.]

Maritain, Jacques. Christianity and Democracy: The Rights of Man and The Natural Law. San Francisco: Ignatius Press, 2011.

Murray, John Courtney, SJ. We Hold These Truths: Catholic Reflections on the American Proposition. Lanham: Rowman & Littlefield, 2005.

Simon, Yves. A General Theory of Authority. Repr. Ed. Notre Dame: University of Notre Dame Press, 1991.

Simon, Yves. Philosophy of Democratic Government. Notre Dame: University of Notre Dame Press, 1993. [While the title suggests this book is focused on democracy specifically, this is probably the best contemporary introduction to Thomistic political thought.]

1. General Textbooks

Austriaco, Nicanor Pier Giorgio, OP. Biomedicine and Beatitude: An Introduction to Catholic Bioethics. Catholic Moral Thought. Washington, DC: The Catholic University of America Press, 2011.

Eberl, Jason. Thomistic Principles and Bioethics. London: Routledge, 2006.

2. When Does Human Life Begin? (See sections on Abortion)

Amerini, Fabrizio. Aquinas On the Beginning and End of Human Life. Translated by Mark Henninger. Cambridge, MA: Harvard University Press, 2013.

Anscombe, G. E. M. "The Early Embryo: Theoretical Doubts and Practical Certainties." In Faith in a Hard Ground: Essays on Religion, Philosophy and Ethics by G. E. M. Anscombe, edited by Mary Geach and Luke Gormally. St. Andrews Studies in Philosophy and Public Affairs. Charlottesville, VA: Imprint Academic, 2008.

Ashley, Benedict, OP, and Albert Moraczewski, OP. “Is the Biological Subject of Human Rights Present from Conception?” In The Fetal Tissue Issure: Medical and Ethical Aspects, edited by Peter Cataldo and Albert Moraczewski. Braintree, MA: The Pope John Center, 1994.

Condic, Samuel B., and Maureen Lenore Condic. Human Embryos, Human Beings: A Scientific & Philosophical Approach. Washington, DC: The Catholic University of America Press, 2018.

Donceel, Joseph. “Immediate Animization and Delayed Hominization.” Theological Studies 31, no. 1 (1970): 76–105.

Eberl, Jason. “Aquinas’s Account of Human Embryogenesis and Recent Interpretations.” Journal of Medicine and Philosophy 30 (2005): 379–94.

Heaney, Stephen. “Aquinas and the Presence of the Human Rational Soul in the Early Embryo.” The Thomist 56, no. 1 (1992): 19–48.

Johnson, Mark. “Quaestio Disputata: Delayed Hominization: Reflections on Some Recent Catholic Claims for Delayed Hominization.” Theological Studies 56 (1995): 743–63.

Johnson, Mark. “Quaestio Disputata: Delayed Hominization: A Rejoinder to Thomas Shannon.” Theological Studies 58 (1997): 708–14.

Kenny, Anthony. “The Beginning of Individual Human Life.” Daedalus 173, no. 1 (2008): 15–22.

Meyer, John. “Embryonic Personhood, Human Nature, and Rational Ensoulment.” The Heythrop Journal 47, no. 2 (2006): 206–25.

Pasnau, Robert. “When Human Life Begins?” In Thomas Aquinas on Human Nature: A Philosophical Study of Summa theologiae 1a 75-89, 100–130. New York: Cambridge University Press, 2004.

Shannon, Thomas. “Quaestio Disputata: Delayed Hominization: A Response to Mark Johnson.” Theological Studies 57 (1996): 731–34.

Silva, José Filipe. “Potentially Human? Aquinas on Aristotle on Human Generation.” British Journal for the History of Philosophy 23, no. 1 (2015): 3–21.

3. Abortion

Lee, Patrick. Abortion and Unborn Human Life. 2nd ed. Washington, DC: The Catholic University of America Press, 2010.

4. Contraception / Birth Control

Anscombe, G. E. M. Faith in a Hard Ground: Essays on Religion, Philosophy and Ethics by G. E. M. Anscombe. Edited by Mary Geach and Luke Gormally. St. Andrews Studies in Philosophy and Public Affairs. Charlottesville, VA: Imprint Academic, 2008.

• "Contraception and Chastity"

• "On Humanae Vitae"

• "Address to the Clergy: On Contraception and Natural Family Planning"

• "Contraception, Chastity and the Vocation of Marriage"

Noonan, John T., Jr. Contraception: A History of Its Treatment by the Catholic Theologians and Canonists. Enlarged ed. Cambridge, Mass: Harvard University Press, 1986.

Smith, Janet. Humanae Vitae: A Generation Later. Washington, DC: The Catholic University of America Press, 1991.

Smith, Janet. Self-Gift: Humanae Vitae and the Thought of John Paul II. Steubenville, OH: Emmaus Academic, 2018.

Smith, Janet. Why Humanae Vitae was Right: A Reader. San Francisco, CA: Ignatius Press, 1993.

5. Euthanasia / Suicide

Anscombe, G. E. M. "Murder and the Morality of Euthanasia." In Human Life, Action and Ethics, edited by Mary Geach and Luke Gormally. St. Andrews Studies in Philosophy and Public Affairs. Charlottesville, VA: Imprint Academic, 2005.

Dewan, Lawrence, OP. “Death in the Setting of Divine Wisdom: The Doctrine of St. Thomas Aquinas," and "Suicide as a Belligerent Tactic: Thomistic Reflections." In Wisdom, Law, and Virtue: Essays in Thomistic Ethics, 326–35, 336–45. Moral Philosophy and Moral Theology. New York: Fordham University Press, 2008.

6. Organ Transplantation (and When Does Human Life End?)

Eberl, Jason. “A Thomistic Defense of Whole-Brain Death.” The Linacre Quarterly 82, no. 3 (2015): 235–50.

Jensen, Steven, ed. The Ethics of Organ Transplantation. Washington, DC: The Catholic University of America Press, 2011.