I have been spending my mornings and evenings working through J.D. Manton’s Introduction to Theological German. Albeit a little old and dated–it looks like it was typed with an old typewriter–it is nevertheless a very good way to get learn German. I have tried on a number of occasions to learn how to read German so that I can read the works Bultmann, Schlatter, Grässer, and others, but I often got overwhelmed with the grammars I was using. With Manton, sentence structure has finally sunk in and I am beginning to see the light at the end of the tunnel, and I am excited. So, if you are looking for a good introduction for theological German I would recommend Manton’s work.