Scott McCloud argues passionately that there is nothing intrinsic to the format of comics that stops it being Art -- and in fact, that there is something to the format, "Sequential Art", that allows it to do things simply not possible with other formats.
Writing in the style he is arguing for, McCloud leads us through some of the conventions that have evolved over the lifetime of comics, such as depicting motion and time, the iconography, why foreground characters and backgrounds may be drawn with different degrees of realism, and the different kinds of transition between panels -- including how these styles have evolved subtly differently in Japan and the West. I have subliminally noticed some of these techniques and styles, so it is fascinating to have them made explicit like this.
His main argument is that the art form allows something to happen "in the gutter", in the space between the panels, that is, in the reader's head. And that this is a kind of thing that doesn't happen in other graphic art forms, like single pictures (there are no gutters) or films (there is no time for it to happen). This is the kind of process that Lois McMaster Bujold refers to in her essay "The Unsung Collaborator". In Donald Norman's terminology, comics is a "reflective" rather than an "experiential" medium.
All in all, this makes deeply interesting reading. If you read comics already, it will help you appreciate how some of the effects are achieved. If you don't, because comics are just "trashy kids' stuff", this may very well change your mind -- about the format, if not about all of its instantiations, at least.
McCloud continues his analysis of comics, here focussing on the wider social, political, economic, and technological context, both past and future.
For me, this isn't as fascinating as his previous Understanding Comics, which is about what's going on in the work itself. But that's probably because I'm a (patchy) reader, not a writer or publisher. There is a lot of historical context, which might interest the aficionado (although I'm dubious about outsiders stating what insiders will like: the phrase "this film will appeal to sci-fi [sic] fans" usually indicates that it most certainly will not!)
The parts that appealed to me the most were (unsurprisingly) the technology issues: both the computer-based direct delivery to the customer, potentially removing many of the difficult marketing issues (whilst creating new ones, of course), and the new opportunities available with computer-based generation and display. Unfortunately (for me!) this is only a small section towards the end -- although I suspect that his next work, Making Comics, may explore this in more detail.
I also felt that the comic-based presentation style itself didn't support the story being told as much as it did previously. This may be because in Understanding Comics there was much more explicit self-reference and illustration, whereas here, the closest to self-reference is about the new delivery forms (computer-based), being explained in the old delivery format (dead trees). Also, I didn't feel there was that much happening "in the gutters".
McCloud makes predictions, and makes the very important point about technology predictions: when about the immediate future, they tend to be overblown, but when about the further future, they tend to be much too conservative. I'm reading this nearly a decade after it was written: some of the predictions have certainly come true (those mostly based on Moore's law increase in computer power), but we are still waiting for those easy micro-payments. In fact, we might have taken a different route (Web advertising along with free content) that has made this path impossible.
In this third book in his series about comics, McCloud (drawn rather greyer and, as he puts it, "rounder", than in his earlier incarnations) concentrates on how to layout, plot, characterise, letter, and draw. He doesn't go into detail about specific styles, as he says, there are many books on how to draw superheroes, etc. He concentrates on the other details -- how many frames needed for an action scene, the muscles behind facial expressions, use of body language, the balance between picture and text and how they together add up to more than each alone, and the tools of the craft, from pencils to computer software.
The comic book style fits the material better here than in Reinventing Comics: it is more self-referential, with the style itself embodying and explaining the material. Although I'm not, and have no pretensions to be, a comic maker, I think that some of the discussion here will help give me a better appreciation of the style. I particularly like the contrast between Manga and US Action Hero styles. And I love the little details about the tools artists prefer, and advice on buying up lots of stock when you find your perfect pen, because it will go out of production.