A brilliant concept—the protagonist is a Christian missionary who travels to another planet to spread the faith—but too many interesting ideas and ramifications of this concept are left totally unexplored. I loved the part when he first arrives at the alien settlement, only to discover that they already know about Christianity. The Catholic church contains many stories like this from the period of European exploration of the Americas. Tracing the implications of such a miraculous event would be fascinating, but no, it turns out they merely had a previous missionary living among them. Lots of moments like this fill the book: a surprising or fascinating turn, ultimately dropped by Faber.