Nachhaltigkeit ist für Jeden. When Sustainability is for Everyone was first published in 2013, the first translation was in German, funded by the Austrian government and produced by the Institute for Sustainability Management at the University of Vienna. That was a time when books were still mostly on paper, and after an initial print run — the book was mainly distributed for free by the Austrian Ministry for a Livable Future (as it was called then) — the book fell out of production in German.
Now it is back, with a new German website. You can download it for free in PDF format or purchase it from any major online bookseller (or any real physical bookstore, though it usually requires a special order).