While this specific German-language edition may be out of print, you can occasionally find used copies through international retailers:
You can view a broader list of Michael Kolberg's technical works on LibraryThing . Word 2003. Das kompakte Know-how zum perfekten ...
If you are looking for general instructions on how to use Word 2003 today, digital archives like the Internet Archive host similar comprehensive manuals such as "Microsoft Office Word 2003 Complete". While this specific German-language edition may be out
Listings sometimes appear on platforms like Amazon.de or eBay. Word 2003. Das kompakte Know-how zum perfekten ...
Microsoft Office Word 2003 complete course - Internet Archive
The book you are looking for is titled (Word 2003: Compact Know-how for the Perfect Use of Word).