I'm not a BVB fan but credit where it's due the Yellow Wall podcast managed to arrange for Uli Hesse to be on the show for their 50th episode. Uli is the author of the wonderful book - Tor! The book describes the history of German football from the very start back in the 19th century.
The book is eminently readable and not at all dry as some books like this can be. As Uli himself says there are not many books about German football translated into English - there may in fact just be one - but Tor! is a great one IMO at least!
You can hear a little from Uli in the second half of the 50th episode on the link below. You can just go and make a cup of coffee whilst they are talking about Dortmund ;)
http://www.tyw.bundesligalounge.com/2013/10/09/special-episode-50/