I just finished reading the translation of Oswald Bayer's ,,Theologie" which in English is entitled ,,Theology the Lutheran Way". The book is a solid presentation of Luther's theological approach. The first part deals with Luther, and Bayer presents his text via two methods: 1. we passively receive Christ's gifts, and 2. theology is undertaken by Scriptural study, trials, and prayers. Bayer also puts forward the thesis that theology is both academic and liturgical, and therefore both sides of theology must remain together, even if they do so in tension. That is a classic Lutheran approach.
The translation of this work is exceptional. The German language can be verbose (by American English standards), but the translator has treated us to a smooth and easy to read translation of Bayer's text. I highly recommend it.
Two other books written by Bayer have been translated into English: ,,Living by Faith: Justification and Sanctification," and ,,Martin Luther's Theology". I have both of these books as well, and I am in the process of reading his ,,Living by Faith".
Check out this link on Bayer's biography.
Also see the website for the University of Tübingen. Bayer was a professor of systematic theology for many years at Tübingen.