Theology
Ignatius Catholic Study Bible: New Testament ed. Scott Hahn
A Catholic Introduction to the Bible: The Old Testament by John Bergsma & Brant Pitre
Mere Christianity by C.S. Lewis
Confessions by St. Augustine
Orthodoxy by G.K. Chesterton
Life of Christ by Fulton J. Sheen
The Case for Jesus: The Biblical and Historical Evidence for Christ by Brant Pitre
Summa Theologica by Thomas Aquinas

Theism (Philosophy of Religion)
The Blackwell Companion to Natural Theology ed. William Lane Craig
God and Moral Obligation by C. Stephen Evans
An Introduction to the Philosophy of Religion by Brian Davies
How Reason Can Lead to God by Joshua Rasmussen
Necessary Existence by Alexander Pruss & Joshua Rasmussen
The Existence of God by Richard Swinburne

Abortion
The Ethics of Abortion: Women's Rights, Human Life, and the Question of Justice by Christopher Kaczor
Abortion & Unborn Human Life by Patrick Lee
A Defense of Abortion by David Boonin
Thinking Critically About Abortion: Why Most Abortions Aren’t Wrong & Why All Abortions Should Be Legal by Nathan Nobis and Kristina Grob

Atheism (Philosophy of Religion)
Logic and Theism by Jordan Howard Sobel
Atheism: A Philosophical Justification by Michael Martin
Arguing about Gods by Graham Oppy
The Cambridge Companion to Atheism ed. Michael Martin
The Miracle of Theism: Arguments For and Against the Existence of God by J.L. Mackie

Ethics (Secular and Traditional Morality)
Practical Ethics by Peter Singer
The Nicomachean Ethics by Aristotle
Utilitarianism by John Stuart Mill
Moral Theory: A Non-Consequentialist Approach
Applied Ethics: A Non-Consequentialist Approach by David S. Oderberg