Saint Ambrose 
The Sacred Writings of Saint Ambrose [EPUB ebook] 

‘The Sacred Writings Of …’ provides you with the essential works among the Early Christian writings. The volumes cover the beginning of Christianity until before the promulgation of the Nicene Creed at the First Council of Nicaea.
Aurelius Ambrosius, better known in English as Saint Ambrose (c. between 337 and 340 – 4 April 397), was a bishop of Milan who became one of the most influential ecclesiastical figures of the 4th century. He was one of the four original doctors of the Church. (courtesy of wikipedia.com)
This edition includes the following writings:
Prolegomena to St. Ambrose.
On the Duties of the Clergy. Introduction.
Three Books on the Duties of the Clergy.
Introduction to the Three Books of St. Ambrose on the Holy Spirit
Three Books on the Holy Spirit.
The Two Books on the Decease of His Brother Saytrus.
Exposition of the Christian Faith
On the Mysteries. Introduction.
The Book Concerning the Mysteries.
Two Books Concerning Repentance.
Note on the Penitential Discipline of the Early Church.
Concerning Virgins. Introduction.
Three Books Concerning Virgins
Concerning Widows. Introduction.
The Treatise Concerning Widows.
Selections from the Letters of St. Ambrose.