The background: Luther as a late medieval theologian 1509-14
Headwaters of the Reformation at Wittenberg: humanism, nominalism, and the Augustinian tradition
Mira et nova diffinitio iustitiae: Luther's discovery of the righteousness of God.
Luther's theology of the cross : Martin Luther's theological breakthrough by Alister E. McGrath. ISBN 9780470655306. Published by Wiley-Blackwell in 2011. Publication and catalogue information, links to buy online and reader comments.