Having recently read a book by Vignelli, and then a fairly straightforward, grid-based introduction to typography, my immediate gut reaction to looking at this book was 'Why did I ever want this?!'. After about 5 minutes of flicking through, my brain settled down, and I remembered.
David Carson's output is visually similar to a lot of, ahem, postmodern deconstructionist work, but it's anything but academic. His experimentation was the graphic design behind real, published magazines, and initially at least his designs stemmed not so much from a desire to break the traditional rules of graphic design as from a lack of interest in them.
Critically, people complained about this rule-breaking for the fun of it, but also about the problems of legibility and graphic identity when things are so chopped up, and the rules never stay constant. Personally, I think that by forcing the reader to think harder to extract the text from the page, by challenging them, you can get the reader far more involved. While the 'rules' of the document may be constantly changing, the underlying 'meta-style' of a lack of consistent design is actually a very strong identity amongst a sea of unadventurous grid-based designs.
Amusingly, one of the other critical reactions is annoyance at the lack of manifesto. Carson generally seemed to refuse to come out and lay down the law on what things should be about, unambiguously explaining goals or anything like that. In other words, designers were annoyed that he got on and designed things, rather than sit about theorizing about the approach! In this collection of his work he does discuss his work a little more, and I must admit I found Blackwell far less grating than in 20th Century Typography.
My first book on typography was Typography Now, so I've always had a soft spot for Carson-style nutty designs. Recently, I've been getting much more into the modernist school of things, and I hope I have a more balanced interest in the subject, but this book really does remind me of why it's so fun to just tear up the rule book from time to time.