Questions of authority shape every element of Christian faith and practice. In Luther's theological development these questions were critical; his challenge to the inherited authority structures of his time and guild determined much of the course of the early Reformation. The eight essays in this volume focus on aspects of his employment of biblical and patristic authorities as his redefinition of what it means to be Christian moved from a ritualistic, hierarchical understanding to a faith based on listening to God's Word and responding in trust, with its resulting praise of God and love for neighbour.

In the longest essay, about one-third of the volume, Stefano Leoni presents a meticulously-researched, carefully-constructed argument for not only one but two key ‘breakthroughs’ or, in his word, ‘conversions’, that reshaped Luther's thinking into his evangelical theology. The first, not recognised previously, was preceded by a shift that moved from a ‘substantial’ to a ‘relational’ view of reality while the professor was still ‘pelagian’ in his soteriology. This move paved the way for his discovery of Augustine's understanding of grace, which prepared Luther to fill in other elements that constituted his mature thought. Although I favour viewing his coming to his evangelical convictions as a maturation rather than an event that can be defined at a specific time or text, the discussion of the reformer's Augustinian turn is most helpful in tracing the growth of his biblical way of thinking.

Likewise, Volker Leppin's essay demonstrates how the conflict between Luther and Johannes Eck before, during and after their confrontation in Leipzig (1519) moved Luther from an acceptance of the authority of popes, bishop, Fathers and councils alongside Scripture in stages to his conviction that Scripture stands alone as the ultimate authority for faith and life. Jun Matsuura argues that in the Assertio omnium articulorum (December 1520) Luther clearly treated the question of authority as the core problem demanding attention and coordinated his solus Christus and the proper distinction of law and Gospel with the principle that the Scripture, taken as a whole with a recognition of its structure, interprets itself.

Further essays explore the reception of Augustine in lectures by Luther and Johannes Bugenhagen on the Psalms (Volker Gummelt); the use of authorities in the 1516 disputation of Bartholomäus Bernhardi on human powers apart from grace (Matthias Mikoteit), and in the 1517 disputation for Franz Günther on scholastic theology (Ingo Klitzsch); Luther's use of canon law in 1518 (Christopher Voigt-Goy), and of Augustine's Retractationes against Jacob Latomus (Hannegreth Grundmann).

These essays carry readers into critical sources from Luther's development in the 1510s and illuminate his struggle for clarity on the path to certainty on the basis no longer of interpreters invested with authority by the Church but rather of God's own voice addressing him from the Bible's pages, as he had come to experience it in wrestling with the Psalms and Paul and with his own doubts and despair. The collection offers most helpful critical source analysis and wider theological perspectives for the benefit of its readers. With its vital insights it will spur further discussion of important questions.