Wool has been on my radar for a little while - at least since Hank Green mentioned it in one of his Stanley Parable videos. Every so often, I'd go to the book store with a little spending money and check a few sections for it (is it fiction? is it science fiction? is it... fantasy? mystery?) and always left with something else instead. 
 After at least a year of this, I finally looked it up. Apparently, Wool isn't sold in stores. You have to buy it online. Well, that's nice, I got it from the library. 
 A lot of the buzz surrounding the book is that its world is immersive (as Justin Cronin's blurb on the front cover has it: "You will live in this world"). And that's certainly been my impression. The location does feel very tangible, even if there were a few fuzzy areas. Namely, that each level seemed to be very single purpose, but surely that must mean that some levels are much smaller than others. Would a nursery floor (what the maternity wards seem to be called - the practice of segregated nurseries seems very odd and out-dated) be as large as the farming floor? Are there apartments beyond the nursery? Do people trying to get home after a shift have to walk through the nursery in order to reach their homes? 
 But the fact that I spent so much time trying to envision the silo and how it's supposed to work isn't really a strike against the book. It means that the silo felt real enough for something fuzzy to stand out. 
 There were a few weak moments in the book. One was with the characterization of Jules - I found it difficult to really grasp her. When she's first introduced, she's completely uninterested in the outside. She can't be bothered with it, she can't understand the obsession with seeing the screens or cleaning the sensors. She's happy in Mechanical, and she urges other characters to focus on the silo, not on the outside. But then, soon after she takes over as the POV character, we find out that she used to pour over children's picture books and dream of the outside. Right from childhood, she is described as having been a dreamer for the broader world. This is a detail that doesn't come up again. It is merely brought up, out of the blue and contrary to the character we've been getting to know up until that point, and then dropped. 
 This grasp of characters may be a bigger problem. I noticed it with other POV characters, like Jahns and Holsten. They seem distinct when we first meet them through the eyes of a different character, but once they slide into the control chair, they all start to seem very much alike. Jahns becomes very much like Holsten, and Jules becomes very much like them both. By the end, where the narrative bounces back and forth between two primary POV characters, they are largely indistinguishable in voice. 
 I also found that the narrative loses a lot of focus near the middle. There are a few chapters there (I noted this observation on p.282 in my copy) where the writing quality drops very suddenly. Throughout that portion, characters seem to be acting based on authorial need (like when Jules doesn't wonder how the plants could be growing in pitch dark - since the author knows that the silo does in fact still have power), rather than their own drives. 
 But these are relatively minor gripes. The world is compelling, and the mystery carries the story quite well until the characters grew on me. There were times when I found myself reading almost breathlessly, desperate to see how the characters get out of the latest jam. Setting up a few POV character deaths early on, combined with some flash forward trickery, raised the stakes. I couldn't trust that the main characters would survive, and had evidence to believe that they wouldn't. It made reaching the end quite thrilling. 
 Where the book suffered, it seems to have been a victim of its publishing history. The serial aspect of it, combined with the lack of an editor, would explain the variations in quality and occasional lack of consistency. But I am, of course, being nit-picky, as usual. 
 Having now read the book, I'm not sure whether I will be ordering it or not. It was an enjoyable read, but I don't know if it was an enduring read - something I'll want to come back to again and again in future, something I'll want to lend out for others to share. That's the trouble with novels that rely too strongly on a "mystery box" - once the answer is known, there needs to be something else for readers to come back to. I think that Wool comes close, and does try to have some profundities about human nature and such, but the ideas were too shallow, too overshadowed by the mystery to stand on their own. 
 On the name: Like others, I puzzled over the name. It's strange, and there's no wool in the book (as far as I can tell). There is, however, the expression "pull the wool over their eyes," which is the central theme of the book.