Ben Reiniger wrote on Wed, Apr 17, 2013 09:57 PM UTC:
It seems this entire book is now available as a free eBook.
http://books.google.com/books?id=XbbhY4Q6U0IC
I don't read German, but it looks like the book is entirely about the 8x8x8 version. (There's some mention of different sizes, but I don't see any mention of a 5x5x5.) Interestingly, the pieces are set up on the first two levels (instead of opposite levels as the 5x5x5).