Irenaeus, Against Heresies, trans. Alexander Roberts and W. H. Rambaut, is free via Verbum.
Irenaeus, Demonstration of Apostolic Preaching, trans. J. Armitage Robinson, is $0.99 via Verbum as a companion deal to Irenaeus’s Against Heresies.
Via mobile ed, the Logos Pro Team has made available for free “a case study on Jonah 1:1-16, [through which] you’ll learn to Observe, Interpret, and Apply the Bible, an efficient and rewarding method you can use with any passage of Scripture.”
Beginning students of theology and church leaders looking for a theological refresher or teaching tool will welcome this remarkably clear introduction to the doctrines of Scripture. In an almost conversational style, Salvation Belongs to the Lord explores all the major biblical truths, explains key terms of systematic theology, and reflects on their implications and connections under the lordship of Christ.