There is still a staggering number of German breweries operating, from brewpubs to global brand names. While it could be argued that only a small percentage of these produce very exciting beers, it is worth noting that all this brewing activity also leads to secondary industries. Among those you have publishers specializing in beer and brewery books, and I came across Hans Carl. They have been publishing brewery books and periodicals for almost 150 years, and they have an online catalogue which makes interesting browsing.
Most of the books are obviously in German, but some have parallel editions in English. The titles range from the purely technical to reference books such as a hop atlas. There is a Katechismus der Brauerei-Praxis, German-English, German-Spanish and German-Chinese brewery dictionaries, an address list of German brewers than run to 432 pages... There is even a bargain section with very attractive prices – you can pick up a primer on the chemical and technical aspects of bottle washing for the price of a glass of beer.