I've been a fan of Robert Charles Wilson for a couple of decades now, since 1992's A Hidden Place. I've enjoyed his generally understated, off-center and off-balance view of the world. So I picked up Spin soon after it came out. While I don't think Spin and its sequel Axis are his best work, they're good. Spin was better than Axis, so I felt some trepidation about Vortex. But once I get more than one book into a series, I tend to continue (unless, as with Robert Jordan, it's impossible to do so), so I bought it.
I'm happy to say that Vortex is better than the preceding two books. It picks up the stories of Turk Findley and Isaac Dvali, and winds in a few new and interesting characters. Across (as Wilson might say) a bridge of years, two intertwined stories unfold, one about a therapist, a policeman, and a troubled young man in post-Spin years, and another about Turk and a companion picked up by a 'limbic democracy' intent on meeting the Hypotheticals.
It's a good story, told in Wilson's standard detached tone, with interesting characters, and intriguing backstory. While some of the plot mechanism (a key Hypothetical device) is underexplained, I was amazed at Wilson's ability to pull all the mechanical threads together in a convincing and generally satisfying way. There's even an interesting epilogue that, if it doesn't quite fit the story, is still interesting to read.
All in all, a satisfying read, and a surprisingly effective end to the trilogy.