This book is weird.
Most of Impact's stuff is kind of shit, but this one is actually quite good as an overview of western comicmaking. It's not random scam artist shit inside, there's a bunch of industry pros from back then and earlier who were consulted and the art is almost exclusively good shit.
It IS relatively small but gets a beginner up to speed on a huge number of concepts in a bit of a rapid-fire manner. Nothing is really gone into too deep but it's a great starting point for doing comics yourself IMO.