I bought the Chlapik book when starting out engraving (some 20 years ago) and German is my native language, so I dare to say I understand what he writes.
The title Die Praxis des Notengraphikers
already narrows down its contents to a description of a music typesetter's practice
. Although he differentiates his examples in good and bad ones and thus is giving rules for music notation, his main point is describing the craftmanship. He emphasizes the artistic aspect of his work by using the word "Notengraphiker" ("Graphiker"=graphic designer). The book is from 1985, I do have the second edition from 1991 (today's spelling since 2004 would be "Grafiker").
The subtitle is "Wie entstehen unsere Noten?" which possibly should make the book interesting for a lay audience.
After describing the history of music engraving and discussing (and abandoning...) various newer develpments like music typewriters
, he has a chapter on computer-aided music typesetting which is totally outdated from today's point of view.
He explains measurement units like Rastral, Zwischenraumzahlen and horizontal note spacing based on Achtelabständen. He elaborates on beaming, beam angles, clefs, key signatures, correct placements of accidentals (has helped me a lot), dots, barlines, rests, fermatas/ceasuras, cue notes, slur placement, multiple voices in one staff, triplets, articulations, grace notes, tempo markings, measure numbering etc. .
Chlapik then gives rules and suggestions for specific instruments like piano and organ and for scores in general. Lyrics are discussed extensively, even covering yodel syllables. He finishes this chapter with further explanations on percussion instruments and text typesetting.
The book can serve as a reference, but has a notable emphasis on the history, the craftmanship and of personal experience and judgement. In the preface, Chlapik explains that the book was written on behalf of his employer, Musikverlag Doblinger in Vienna, as a reference (and "Arbeitsanleitung"=working instruction) for later music engravers. The book is mainly of historic interest as a snapshot of music engraving as an artistic craft.