And even in the context of published Trek books, Franz Joseph's Technical Manual basically amounts to nothing more than an oddball curiosity now. FJ actually wasn't a fan of Trek... he thought it was rather silly with all the scientific inaccuracies. Not that being a fan is some kind of prerequisite, but that's neither here nor there for this discussion. FJ just came up with this interesting project of trying to make some kind of technical design sense of the stuff that had been seen or mentioned in the show (and in some instances, correcting stuff that didn't make sense), as well as doing some extrapolations, which at the time was fair game since it seemed that Trek on screen was dead.
Anyway, FJ had Gene R.'s support in the beginning, but at some point there was a falling-out, and GR started discrediting FJ's work. And Trek has diverged from it ever since.
Kor