We are grateful to our friends at Traditional Catholic for their extensive research in finding the following resources.
Douay-Rheims Roman Catholic Bible – read online
Biblia Sacra Vulgata (Latin Clementine Vulgate Bible) – read online; or pdf here: latin; english
The Knox Bible – read online (trilingual: english Knox translation/greek Septuagint/latin Vulgata)
The Catechism of the Council of Trent (Catechism of St. Pius V) – pdf
Catechism of St. Pius X – read online
The Douay Catechism (1649) – pdf
The Baltimore Catechism (1891) – pdf; or audio version here
The Catechism Explained (Fr. F. Spirago) – pdf, text, kindle format
A Complete Catechism of the Catholic Religion (Fr. Joseph Deharbe) – pdf, text, kindle format
My Catholic Faith: A Catechism in Pictures (Mons. Louis Laravoire Morrow) – read online
Catechism Made Easy: A Familiar Explanation of the Catechism of Christian Doctrine (Fr. Henry Gibson) – pdf, text, kindle format: volume I, volume II, volume III
Anecdotes and Examples Illustrating the Catholic Catechism (Fr. F. Spirago) – pdf, text, kindle format
Catechism on Modernism according to the encyclical ‘Pascendi Dominici Gregis’ of His Holiness Pius X (J.B. Lemius) – pdf, text, kindle format
Summa Theologica (St. Thomas Aquinas) – text, kindle format; or read online here; or in audio format; [parallel latin/english text available here]
Catechism of the Summa Theologica of St. Thomas Aquinas – pdf
The Catechetical Instructions of St. Thomas Aquinas – pdf
A Synthesis of Thomistic Thought (Fr. Reginald Garrigou-Lagrange) – read online
A Tour of the Summa (Mons. Paul J. Glenn) – read online
Sources of Catholic Dogma (Fr. H. J. D. Denzinger) – read online; [latin text here]
Fundamentals of Catholic Dogma (Ludwig Ott) – pdf
Dogmatic Canons and Decrees – pdf, text, kindle format
Christian Doctrine (Laurence Vaux) – read online
The Canons and Decrees of the Council of Trent – pdf, text, kindle format; or read online here
Dogmatic Theology I. God: His Knowability, Essence, Attributes (Mons. J. Pohle) – pdf, text, kindle
Dogmatic Theology II. The Divine Trinity (Mons. Joseph Pohle) – pdf, text, kindle format
Dogmatic Theology III. God: The Author of Nature and the Supernatural (Mons. J. Pohle)– pdf, kindle
Dogmatic Theology IV. Christology (Mons. Joseph Pohle) – pdf, text, kindle format
Dogmatic Theology V. Soteriology: A Dogmatic Treatise on the Redemption (J. Pohle) – pdf, kindle
Dogmatic Theology VI. Mariology: A Dogmatic Treatise on the Blessed Virgin Mary (Mons. Joseph Pohle) – pdf, text, kindle format
Dogmatic Theology VII. Grace, Actual and Habitual (Mons. J. Pohle) – pdf, text, kindle format
Dogmatic Theology VIII. The Sacraments, Vol. 1: Baptism, Confirmation (J. Pohle) – pdf, text, kindle
Dogmatic Theology IX. The Sacraments, Vol. 2: The Holy Eucharist (J. Pohle) – pdf, text, kindle
Dogmatic Theology X. The Sacraments, Vol. 3: Penance (Mons. J. Pohle) – pdf, text, kindle format
Dogmatic Theology XI. The Sacraments, Vol. 4: Extreme Unction, Holy Orders, Matrimony (Mons. J. Pohle) – pdf, text, kindle format
Dogmatic Theology XII. Eschatology: The Catholic Doctrine of the Last Things (J. Pohle) – pdf, kindle
A Handbook of Moral Theology (Anton Koch) – pdf, text, kindle format: volume I, volume II, volume III
The Enchiridion of Indulgences (1968) – pdf
The Raccolta or Collection of Indulgenced Prayers and Good Works (1910) – pdf; or pdf, text and kindle format here
The Roman Martyrology (1916) – pdf, text version; or read online here
The Liturgical Year (Dom Prosper Gueranger) – read online; or pdfs here
The Church’s Year: Explanation of the Epistles and Gospels (Fr. Leonhard Goffine) – read online; or pdf, text, kindle format here
Goffine’s Devout Instructions on the Epistles and Gospels – pdf, text, kindle format
Introduction to the Study of Holy Scripture (A. E. Breen) – pdf, text, kindle format
Practical Handbook for the Study of the Bible (M. Seisenberger) – pdf, text, kindle format
Haydock’s Bible Commentary (Fr. G. L. Haydock) – read online
A Practical Commentary on Holy Scripture (Bp. F. J. Knecht) – pdf
Cornelius a Lapide: The Great Commentary [on Scripture]- vol. 1, vol. 2, vol. 3, vol. 4, vol. 5, vol. 6, vol. 7, vol. 8
Catena Aurea (St. Thomas Aquinas) – read online (commentaries on the Gospels)
The Apocalypse of St. John (Fr. Sylvester Berry) – pdf, text, kindle format
The Apocalypse of St. John (Fr. H. M. Feret) – pdf