It is my first comment on slashdot so be patient with me.
At first: Thank you for the review. I am proud to reach 7 of 10 points :-)
Concerning the German things:
The book is a translation of a German book I wrote in November/December 2007.
It is translated into French, Dutch and as you have seen ... in English. I was talking with all the publishers and ask them whether it is possible to free the content. The German and the French book are now available on-line completely for free.
http://joomla.cocoate.com/de/joomla-15
http://joomla.cocoate.com/fr/joomla-15-fr

I want to use this opportunity to ask you for two favors.
1. Please help me to convince other publishers to free the content of the Joomla! book by writing a comment here at slashdot or (may be better) at the books website
(http://joomla.cocoate.com/de/content/book-review-slashdotorg)
2. At the moment I talk to various people who wants to help me, to translate the online content into other languages (turkish, spanish, ...). If you have time to translate something in another language, send me an email.

I hope you enjoy the book (even if the German touch is strange) and again, thank you for the review.
Hagen