English language from a German native:
Except for Capturing Races 1, my books have been proofread by British English proofreaders, of which most are British or exceptionally Irish. Nevertheless, for a native reader or readers with very good knowledge of the English language, it sometimes is possible to notice that the English language style has the impact of a German native author. In my books, it can be noticed less than in my online messages or than in a number of go books of other authors translated from other languages and not completely rewritten by a native English speaker.
Go Terms:
I prefer English terms to Japanese terms, unless a) the English term is the Japanese term (such as 'ko' or 'gote') or b) an English term would be unnecessarily awkward (such as replacing 'shinogi' by 'strategy / playing style to leave behind weak groups'). I avoid every traditional term that I consider superfluous or useless (such as 'sagari' or 'dog shape'). I invent relevant, necessary or particularly useful new terms (such as 'indirect connection' or 'fighting liberty'). This affects different books differently: Joseki 1 has a number of such terms, because every move type needs a name; Capturing Races 1 has only two such terms, because the other terms were already available. Usually, consistently throughout my texts, I use terms with the same meaning and describe same things by the same terms; where necessary, definitions provide this meaning. Unlike in quite a few books by other authors, the reader need not guess how to translate ordinary English to the right terms, because I use terms as terms and, as far as possible, try to avoid using non-term phrases with the meaning of a term. Terms invented in earlier books and used in later books are at least briefly defined again in their introductions; usually, this affects only a few terms. Where many other books simply use English terms and presume their knowledge, I clarify that they are used as terms, if necessary, define them and then use them in consistent phrases as terms.
IMO, the consistent, clear use of go terms has a much greater impact on the English than introducing a German touch to the English style.
Contents:
The TOCs tell you a lot about the selection of topics in every book:
http://home.snafu.de/jasiek/books.htmlThe contents can differ from English go books by other authors mainly in these aspects: 1) a greater to much greater amount of generalising and explicit theory, 2) invention also of new go theory instead of only repeating already existing go theory (not in First Fundamentals *), 3) completeness where or as far as possible and useful for the kind of presentation of a topic (*), 4) accuracy of generally applicable theory (in case of non-absolute principles, this is so for the intended frequency of correctness of a principle; e.g., if it shall apply in ca. 90% of all cases, then for them application must be correct), 5) as far as already possible, high degree of generality of theory (whether definition, principle or something else; e.g., you do not find "Force before living." as a principle in my books, because it is too specialised; you find a more generally applicable principle instead: "Force before acting.").
Organisation:
The books (*) use a very systematic presentation (such as using clear structure or classification).
Reliability:
See above. AFAIK, in my 7 books so far, I have made only ca. 3 mistakes of go theory altogether: a) suggesting a wrong pronunciation for haengma, b) overlooking a ko in one example, c) showing an opening position with the wrong player to move (but it does not matter for the example; it is an aesthetic mistake). It is an indication for the quality of the go theory that, if anything is criticised at all, it is the imperfect English:) Of course, everybody is invited to find a 4th mistake of go theory.
Accessibility:
The books (*) have detailed TOCs, detailed indexes and bold font for important contents. See also above. Printed and PDF versions are available.
Somethingbility:
The books (*) have a pretty great density of knowledge, so that reading them thrice can be useful. The books can be abused for learning by examples only, if the reader simply ignores all the text and theory; but used for this purpose only, the books are too expensive. Except for problem books to be written later, the books have relatively few problems; readers wishing something like 50% problems in the book won't find enough, unless they use suitable examples in the books as further problems. It can sometimes help to read also problem books by other authors, but quite a few topics of go theory lack (enough) problems in the literature so far.