Set almost a melenium in the future, in a universe where man has left a ruined Earth and is stratified into three distinct sects (The Christians, Communists, and Arabs) and has yet to encounter an "equivalent society", Barnes spins a captivating yarn on the freshly discovered world of Randall. In the Christian sphere of influence a world has been discovered where there are three intelegent species living in symbios. This is a great discovery for those who study alien life, since nothing of the sort has ever been encountered, but for the church there are more impotant considerations--such as converting the heathen aliens and opening the world to settlement.
Against what is a quite serious look at mankind's tendency to repeat his mistakes (It's been done before, yes, but Barnes does it quite well here) and a Resnick-like parable of 18th century European expansion (though focusing on the missionary aspect of it), Barnes has written an engrosing adventure novel that moves at quite a clip and is considerably more impressive than his first novel, The Man Who Pulled Down the Sky (not that that was a bad book by any stretch).
My one complaint would be a somewhat hasty ending--and looking at his first novel and other Asimov Presents that I've glanced at, which all clock in at 250 pages, I imagine that may have been forced by editorial guidelines. And while I'm mentioning editorial stuff: DON'T READ THE INTRODUCTION! Asimov blows a revelation that Barnes does his best to disguise for 240 pages.
Now go find it Barnes fans.