Reiner Hartmann
Unfortunately, there is no information provided about the author Reiner Hartmann in the given documents.
The author's name is mentioned in the book title and author section, but no biographical details or background information is included.
Without additional context, it's not possible to provide a summary about the author's life, qualifications, or other works.
The focus of the available information is primarily on the book itself and readers' reviews of its content, rather than details about the person who wrote it.
