For the Historical Origins of the Problem of the Practicality of Reason, see:
Wyner, Garret: Toward a Phenomenology of Conscientious Action
and a Theory of the Practicality of Reason

Primary Works:
On the Holy Trinity
The Enchiridion
On the Catechising of the Uninstructed
On Faith and the Creed
Concerning Faith of Things Not Seen
On the Profit of Believing
On the Creed: A Sermon to Catehumens
Of Continence
On the Good of Marriage
Of Holy Virgnity
On the Good of Widowhood
On Lying
To Consentius: Against Lying
Of the Work of Monks
On Patience
On Care to be had for the Dead
On the Manichaean Heresy
On the Morals of the Catholic Church
On the Moral of the Manichaeans
On Two Souls, Against the Manichaeans
Acts of Disputation Against Fortunatus the Manichaean
Against the Epistle of Manichaeus called Fundamental
Reply to Faustus the Manichaean
Concerning the Nature of God, Against the Manichaeans
On Baptism, Against the Donatists
Answer to Letters of Petilian, Bishop of Cirta
The Correction of the Donatists
On the Merits and Remission of Sins & On the Baptism of Infants
On the Spirit and the Letter
On Nature and Grace
On Man's Perfection in Righteousness
On the Proceedings of Pelagius
On the Grace of Christ and on Original Sin
On Marriage and Concupiscence
On the Soul and its Origen
Against Two Letters of the Pelagians
On Grace and Free Will
On Rebuke and Grace
On the Predestination of the Saints
On the Gift of Perseverance
Homilies on the Gospel of John
Homilies on the First Epistle of John
Confessions (Chadwick trans)
City of God ((Dods trans, T. Merton Intro)
The Literal Meaning of Genesis 2 Volumes
On the Psalms 2 Volumes
Sermons for Christmas and Epiphany
Against the Academics
The Greatness of the Soul
The Teacher
The Lord's Sermon on the Mount
The First Catechical Instruction
Faith, Hope and Charity
On Free Will (Sparrow trans)