Exceptional. This is required reading if you love comics, like comics, or have a passing interest in maybe checking out the hype surrounding these "comic books" you've heard so much about. 
 (Also, if you're gonna read Scott McCloud's 
 The Sculptor 
 , read this first. I wish I had. A lot of what he does in The Sculptor seems like it's a direct result of the things he learned from writing this book.)