Under the Dome tells the story of a small town that one afternoon is suddenly covered by a clear, near impermeable dome. The citizens of Chester's Mill are forced to cope with this situation, which is complicated by drug deals, rape, murder, and political struggle. The main character is Dale Barbara (called Barbie) a former military man who has become a drifter/short-order cook. He has to figure out what to do about the dome while trying to avoid the clutches of a power-hungry local politician.
The scope of this book is pretty large--aside from Barbie there are probably at least another 50 or so distinct characters, including members from both sides of the dome's conflict as well as "extras." It's a lot to keep a handle on, but King does a pretty good job for the most part. I'd say he did a better job with this same task while writing The Stand, but on the whole I wouldn't say it's bad. The main characters are fairly well-drawn, though the villain can be a bit cartoony. The plot rolls along pretty well, and I plowed through the (admittedly giant) book as fast as I could. I enjoyed it until the last 75 pages or so, where King just fumbles all the strings of the story. The admirable build he managed to keep up throughout the whole book just goes "Ppphhbbt" at the end. In fact, the genesis of the dome (and the way the characters deal with it) is downright stupid. Unfortunately, as much as I love Stephen King, I have to admit that he is shite with endings. Nearly all his books--from IT to The Stand to Christine--have somewhat stupid endings. He builds to a fever pitch, and then there's some stupid mega-alien-spider or a nuclear explosion and things end. Booo!
Despite my disappointment with the ending, I would say that this book is still worth reading. I found it entertaining to read, though it's not going to win any prizes. His style is still fun for me, and I thought the theme of "the politics of fear" (although he mentions that he started this story in 1976, it's clear the majority of it was written with a keen eye observing the Bush era) was interesting. On the whole, it's a decent read, and worth the $9 I paid for it, but it's not the novel of the century or anything.
(As a sidenote, I read someplace that Showtime or somebody is exploring a full-scale mini-series of the book produced by Spielberg, and I think THAT could be great, depending on who they get to write and star.)