"Redemption Ark" is billed as a sequel to Mr. Reynolds's intriguing "Revelation Space, and in some sense it is; but it's much more than that. It brings back a few of the characters--and settings--of its predecessor, but it veers off in a totally unexpected direction. The author introduces plenty of new characters--human, machine, and combinations of the two--and new puzzles. The conflicted warrior Nevil Clavain assumes the hero's role and Skade (of the detachable head) serves as his bizarre opponent.
Clavain is intriguing: like the lonely private eyes of the hardboiled detective tradition, he doesn't always quite know what's going on; and his plans don't always work quite as designed. He battles the life-destroying Inhibitors (machine intelligences that want to "inhibit" intelligent life), the forces unleashed by Skade, and a few others as well. Spaceship captain Antoinette Bax and her mechanic and more than friend Xavier Liu, who are enlisted in Clavain's pickup army, supply the human factor. Their heads aren't detachable, and they don't deal in cosmic issues; they just want to survive. And then there's Scorpio--he's a . . . err, never mind. Best if you see for yourself.
There's plenty of great science here, too. The author, an astronomer by trade, instructs his readers on how to destroy a star, and how a starship might gain sentience of its own. And the author's technique is unorthodox, he writes as though he's saying to his audience, "look--we've all read space operas--we all know how battles go." So he pretty much shows you more of the befores and afters, and less of the action than do many authors. Some may be put off. I thought it was clever.