Internet Resources on Christian Asceticism: http://www.ellopos.net/notebook/resources_f.htm
Christian Classics Ethereal Library:
Extremely helpful source of primary texts in church history, Christian spirituality, Christian music, and more
Lectio Divina: Christian Spiritual Authors:
Index page of sources for spiritual reading; many good primary texts in early Christian theology and spirituality.
“A Hypertext Encyclopedia of Early Church History” (and primary texts)
Patristic Texts, The 1908 Catholic Encyclopedia, Hagiography
The Holy See:
Official Website of the Holy See: papal and curial documents in different languages.
The Spiritual Exercises, St. Ignatius, Ignatian spirituality, and more.
Christian Art, The Holy Land, Papal Documents
Jordan Aumann, O.P. Articles and complete books, including Spiritual Theology and Christian Spirituality in the Catholic Tradition: http://www.domcentral.org/study/aumann/default.htm
Adolphe Tanquerey, S.S., Articles § 1-899 of a classical text, used for several decades as the basic textbook of ascetical/mystical theology in Roman Catholic seminaries: The Spiritual Life, A Treatise On Ascetical And Mystical Theology