This is a handy basic introduction to type design issues. But it is marred by some of the author's eccentric beliefs, stated as facts.
First of all, whatever you think of Helvetica (and I'm not a fan), I don't think it's showing any signs of fading from our public spaces, more's the pity.
Second (and related to the above), her fondness for wacky, eye-catching, "novelty" typefaces is going to lead many people in quite the wrong direction. If you're designing a club flyer or a magazine ad., maybe it's useful advice; but, if taken to heart by a beginner, it would be a disaster for the production of readable, proportioned, pleasing typography in long texts. As for her defence - without cautionary words - of the use of bold italics for emphasis: I'm afraid that just makes me shudder! As a book editor as well as a typesetter myself, I can't tell you how many hours I've had to waste removing such typographical detritus from the texts of authors who should have known better. Now I know where they might have got the idea from...
Finally, a smaller point, which may be to do with a difference between US and British usage, but of which UK users of this book should therefore be aware. To my mind, it is ugly and unwarranted (I'll just come right out and say it: illiterate!) to follow an italicised word or phrase contained within a roman paragraph with italic punctuation (or bold with bold, or whatever - see p. 67). Punctuation outside an emphasised phrase does not belong to that phrase, but forms part of the scaffolding that holds the phrase in place. Like all scaffolding, it shouldn't bend under the influence of what it's supporting, but should damn well stay put! (Don't just take my word for this - see section 6.6 of
The Oxford Manual of Style). Lamentably, though, this does seem to be the general advice offered in most US texts on the subject, including one of the ones I recommend below. (And I'm no knee-jerk opponent of US practice: the so-called "Oxford comma" - prevalent not just in Oxford but in the US, though frowned upon by many UK style guides, and by Lynne Truss, I believe - seems to me like a very sensible thing.)
So, all in all, a useful introductory text; but for a proper grounding in typography - and especially if your main interest is in book design - go instead to
The Elements of Typographic Style and/or
The Complete Manual of Typography: A Guide to Setting Perfect Type.