We are grateful to our friends at Traditional Catholic for their extensive research in finding the following resources.
The Imitation of Christ (Thomas a Kempis) – pdf, text, audio
Uniformity with God’s Will (St. Alphonsus de Liguori) – pdf, text, audio
Humility of Heart (Fr. Gaetano M. da Bergamo) – pdf, text
The Way of Salvation and of Perfection (St. Alphonsus de Liguori)
Abandonment to Divine Providence (Jean-Pierre de Caussade) – pdf, text, audio
Trustful Surrender to Divine Providence (St. Claude de la Colombiere) – pdf
The Spiritual Combat (Fr. Lorenzo Scupoli) – pdf, text, kindle format
The Practice of the Love of Jesus Christ (St. Alphonsus de Liguori) – pdf
Preparation for Death (St. Alphonsus de Liguori) – pdf
The Art of Dying Well (St. Robert Bellarmine) – pdf, text, kindle; also pdf here; or audiobook version here
The Practice of Perfection and Christian Virtues (Fr. Alphonsus Rodriguez) – Vol I (doc format) and Vol II (doc format)
Introduction to the Devout Life (St. Francis of Sales) – pdf, text, audio
The Treatise on the Love of God (St. Francis de Sales) – read online
The Ladder of Divine Ascent (St. John Climacus) – pdf
Little Book of Eternal Wisdom (Bl. Henry Suso) – pdf, text, ibook
Calamities, Chastisement and the Love of God (St. Alphonsus de Liguori) – pdf, text, kindle
The Practice of the Presence of God – The Best Rule for Holy Life (Brother Lawrence) – pdf, text, audio
On Loving God (St. Bernard of Clairvaux) – pdf, text, audio
Holiness of Life (St. Bonaventure) – pdf
The Holy Ways of the Cross (Henri-Marie Bouden) – pdf; or kindle format here
The Interior Life (Fr. J. Tissot, St. Francis de Sales) – pdf, text, kindle format
The Spiritual Exercises of St. Ignatius of Loyola (St. Ignatius) – pdf, text, audio
The End of This Present World and the Mysteries of the Life to Come (Fr. Charles Arminjon) – pdf, text
A Sinner’s Guide (Ven. Luis de Granada) – pdf
A Memorial of Christian Life (Ven. Luis de Granada) – pdf, text, kindle format
All for Jesus: The Easy Ways of Divine Love (Fr. F. G. Faber) – pdf, text, kindle format
Growth in Holiness, Or The Progress of the Spiritual Life (Fr. F. G. Faber) – pdf, text, kindle format
On Union with God (St. Albert the Great) – pdf, text, kindle format
The Three Ages of the Interior Life (Fr. Garrigou-Lagrange) – read online
Spiritual Maxims (J. N. Grou) – pdf
Prayer, the Key of Salvation (Fr. M. Mueller) – pdf, text, kindle format
Prayer: The Great Means of Salvation and of Perfection (St. Alphonsus)
The Ways of Mental Prayer (Dom V. Lehodey) – pdf
An Easy Method of Meditation (Fr. F. X. Schouppe) – pdf
A Golden Treatise of Mental Prayer (St. Peter of Alcantara) – pdf, text
Holy Wisdom: Directions for the Prayer of Contemplation (Fr. Augustine Baker) – pdf
The Art of Mental Prayer (Fr. B. Frost) -pdf
The Paths of Goodness: Some Helpful Thoughts on Spiritual Progress (Fr. E. F. Garesche) – pdf
The Following of Christ (Fr. J. Tauler) – pdf, text, kindle format; or read online and pdf here
The Friendship of Christ (Mons. R. H. Benson) – audiobook; or read online here
The Cloud of Unknowing (Anonymous, 14th cent.) – audiobook
The Wisdom of the Desert (James O. Hannay) – pdf, kindle format
Directorium Asceticum: Guide to the Spiritual Life (Fr. G. B. Scaramelli) – vol. I, vol. II, vol. III, vol. IV
Manual of Christian Perfection (Fr. G. B. Scaramelli; P. J. Stockman) – pdf, text, kindle format
Manual of Self-Knowledge and Christian Perfection (Fr. J. H. Schagemann) – pdf, text, kindle format
Spiritual Theology (Fr. Jordan Aumann) – pdf, text, kindle format
The Spiritual Life: A Treatise on Ascetical and Mystical Theology (Fr. A. Tanqueray) – pdf, kindle
The Mystical Evolution (Fr. J. G. Arintero) – pdf: volume I, volume II
A Manual of Mystical Theology (Fr. A. Devine) – pdf, text, kindle format
Meditations on the Mysteries of Our Holy Faith (Fr. Luis de la Puente) – vol. I, vol. II, vol. III, vol. IV, vol. V, vol. VI