Ante-Nicene Fathers (Vol 1): The Apostolic Fathers, Justin Martyr, Irenaeus

Philip Schaff's classic work colloquially known as Early Church Fathers, is an invaluable resource filled with the primary documents, and early theological building blocks for the Christian Church. Comprised of 38 volumes it is broken into three parts, the Ante-Nicene Fathers, and Nicene and Post-Nicene Fathers, First and Second Series.