I just finished reading Axis, by Robert Charles Wilson, his sequel to Spin. Spin was exceptional. Sadly, Axis doesn't quite achieve the same level. It's not bad. It's perfectly good science fiction. Heck, it's probably even above average, but it's hard to evaluate in an unbiased way, given the my expectations were unreasonably high going in.
So, what was good and not-as-good about Axis? It's going to be easier to rave about Spin and then complain where Axis falls short by comparison, while giving it credit where it's due, so that's how I'll do this. So, Spin was exceptional.
Spin has outstanding characters an engaging and deep plot and good science fiction ideas. But to me what really sets Spin apart is the way it paced it's build up, incremental delivery, and final dramatic payoff. One ubiquitous problem in fiction, especially science fiction, is the story that builds up, builds up, and builds up some more, without giving you any real narrative resolution or "payoff" until the very end. Further, that final payoff often falls short, especially since there's been such a big build up. So, you get a story that builds tension, dramatic energy, and then it turns out that the author was just good a writing tension and dramatic energy, not that the story actually had anywhere to go. Now, some novels, like Snow Crash do this, but the build up is so amazing along the way, it doesn't matter if the payoff is less than satisfying. Heck, something like Rendevous with Rama sort of set the standard in this way by not even really bothering with a payoff at all. In contrast, Spin has none of these failings.
Spin does a lot of build up, but it does a few remarkable things. First, it has that Snow Crash attribute of a compelling milieu for the build-up with great characters such that it doesn't even critically need a payoff. Second, it actually does deliver great incremental payoff. There are multiple points along the story where plot elements are actually resolved rather than just teased at. Finally, the ending payoff is more than just satisfying. It's a creative twist on top of the book, which is full of creative twists. And, as mentioned above, the characters are outstanding. Diane and Jason in particular are compellingly written and deeply familiar characters. And finally, while this is less of a problem in science fiction in general, it doesn't fall prey to the "sit-com syndrome" of having an odd compulsion to reset the state of the universe at the end of the book to match the state at the beginning. So, Spin is exceptional.
Axis is good. It has some incremental payoff. It has some good characters. It's got nice plot elements. But, it doesn't have great characters and it does that standard big build-up thing without having the final payoff to really make it worth it. Actually, let me qualify that. The final payoff is pretty good, even if it's not a total resolution, but so much of the book is tied to that payoff, it's hard for it to succeed. Even some of the interesting sub-plots are unnecessarily held until the end. Overall, I wouldn't strongly recommend Axis, but nor would I suggest you skip it. In contrast, you must read Spin.