this page), sums up the story better than any of the professional covers I've seen. Iron Council is a novel of "power to the people," power against the people, and most especially the power of Christ figures over the people.
Not that I'm trying to pin a religious interpretation on the book; it's not religious, and neither, as far as I can tell, is China Mieville. So if you don't know what a "Christ figure" means in literary terms, have a quick look here before you read on. I don't want to give you the wrong impression.
Now here we go. The most obvious Christ figure in Iron Council is Judah Low, who's so saintly and so powerful that he can turn the tide of a battle by creating "ab-life" from scratch. In other words, he makes golems. And he's pretty damn inventive with them, too. That's supposed to be him riding one of his creations in the second-from-left picture below (by homarusrex, who has a lot of other Mieville-related pics in his Deviant Art gallery, although you'll have to beware of spoilers. Big ones.).
I don't think this is a particularly accurate interpretation of Judah or his golems, but I couldn't find anything more appropriate; and anyway Toro (far left) and Jack Half-a-Prayer (second from right) are a couple of other messiah-figures from Iron Council who IMO look spot-on. I also really like the cactus man. That's exactly how I picture them. As for the guy on the right, he's a crayman from The Scar.
Anyway, Mieville's point about Christ figures seems to be that they really aren't messiahs, just (occasionally) naughty boys - and girls - with a lot of power, charisma, and ego. For instance, Judah can be incredibly annoying and hurtful to those who are closest to him, especially poor Cutter. If Judah is a stand-in for Christ, then Cutter is his John, a.k.a. "the beloved disciple." Or if you're tired of religious analogies, you might think of Cutter as Sam to Judah's Frodo (which, if you've already read Iron Council, should give you a giggle. Just think about it for a second. ;-)).
Really, you probably are tired of messiah-talk by now, so I'll just make one more quick note about that and then pretend I'm an ordinary book lover and not an ex-English teacher. The truest "savior" in Iron Council is presented so subtly that you might overlook his/her Christlike qualities altogether. But maybe now that I've clued you in, you won't. I hope you won't. The character really deserves to be recognized.
But what's the book actually about, eh? And how does it stack up against Perdido Street Station and The Scar? Let me start with the easier question: I liked The Scar best, and I liked all three of the novels, but Iron Council is my least favorite. That's due in part to how bleak it is, even though Mieville managed to pull another bittersweet triumph out of his hat at the last moment. I'm beginning to think it's a trademark of his.* I might also have liked the book better if I hadn't been forced to read it in little chunks with lots of down-time between chapters. Because of that, it lost a lot of (heh) momentum for me. I wonder what it would feel like in a re-read. I suppose I'll find out one day. I normally do read good books more than once.
Cutter and company end up traveling all the way across the continent and, fairly early on, pick up the guy in the picture (by trabbold) at right above. His name is Drogon, and he has a very, very scary power. He can control people, just by whispering words only they can hear. Just imagine the implications of that. And now imagine those implications again, with the knowledge that Drogon only controls people's bodies; their minds are still free, no matter what he makes them do. I've blogged about body control vs. mind control before, and I still find body control pretty horrific by itself. Plus, with Drogon, you don't know whose side he's really on until near the end of the book. That makes him even more of a threat to your nerves.
But that's pretty much all I can tell you about Iron Council without telling you too much. I do recommend it, even though I don't recommend getting too attached to most of its characters. ;-/
*along with overuse of the words palimpsest, cosseted, and jag