As someone who reads and reviews graphic novels from time to time (especially lately!), I could hardly overlook this, and having read it I can say I recommend it. It's pretty basic stuff with regard the artwork (drawn by Dunlavey, colored by Guzowski, and the text (by van Lente) is quite dense at times, so it makes for a long and detailed read, but overall it was truly informative and on occasion eye-opening.
It also features female contributors from history quite prominently, but on the downside, it does not seem to do the same thing for people of color. Whether this is because there were (historically speaking) none in the business, or because what they contributed was relatively little (which i doubt!), or if they were simply overlooked I don't know, but the fact that they're not given a look-in is disturbing. In a similar vein, it features only US comic book creators. It covers nothing of comic book activity outside the USA.
With those limitations in mind, it does seem otherwise quite comprehensive, and it goes into a lot of history, and quirks and fights, and how some aspects of the industry came to fruition, but it doesn't really go into the minutiae of any particular character's creation. This is more focused on the business itself and the key players historically, and some technical aspects of comic production, but it's not so much focused on the actual content the people and business created. For me, I enjoyed it and learned a few things, but I didn't feel it was an outstanding read. It was worthwhile reading though if you're interested in a behind the scenes kind of story, so this is how I rate it.