Dialogue of the Seraphic Virgin Catherine of Siena
Full text of book by St. Catherine of Siena. Algar Thorold translation. Available in several formats.
Divers Doctrines Devout and Fruitful
From Henry Pepwell's little 1521 devotional collection, edited and with notes by Edmund G. Gardner as "The Cell of Self-Knowledge". Extracts from Raymond of Capua's Life of St. Catherine.
Letters of Catherine Benincasa
In plain text (two versions) or as a zip file, from Project Gutenberg.
The Dialogue of the Serafic Virgin Catherine of Si
Algar Thorold translation. Full text, with concordances and word frequency lists.