I own all three of these books, as well as about 20 other books about the comics medium. I've studied them!

Personally, I'd recommend skipping Reinventing Comics, unless you really want to own the entire trilogy... most of the content of it is reductive, or covered better in the other two, and much of it is talking about webcomics as a new phenomenon, and speculating about what the medium might accomplish with digital technology (most of this didn't come to pass, because the amount of effort involved in merging the comic format with programming is prohibitive - with some extremely notable exceptions to this.)

I'm a big fan of Scott McCloud's work in exploring the medium, so here's a little bonus for mentioning him. Other than his observations of the medium, explained to the casual reader in a phenomenally digestable fashion, the two things I know him best for are:

1. "24 hours comic day" - a challenge where comic creators try to create a 24 page comic book in a single day (or in the case of digital comics, 100 panels)

2. His advocacy for use of "the infinite canvas" in sequential art. The infinite canvas is something we're much more used to in the modern day with social media - but the idea is that you "read" the comic simply by scrolling down, and there's no page breaks, you just keep going. Basically it's doomscrolling for comics, but before "doomscrolling" was a thing.

So, I've done 24HCD a few times, and one time I even made a good one!

Here's a comic that I drew in 24 hours, using the infinite canvas.

Enjoy.