PW has a (non-starred) review this week: a summary. Don't read it if you really don't want to know.
Civilization is decaying on Blue, and Horn is sent to find Silk, i.e. a lander capable of returning to the Whorl. He gives us a summary of his own life en route (rather ditheringly), and battles vampires who want to take humans to Green as cattle. The book is slow, but mysteries are established for later volumes. (severely truncated summary)
*This is WHORL, for discussion of Gene Wolfe's Book of the Long Sun.