I've only read two of Andrew Greeley's books, this and the Final Planet, and both were excellent tales. Well written, good story telling, and wonderful characters. In both hisbackground in the Catholic faith comes through strongly, in Angel Fire,its also a clear statement of the interplay of faith and science that sings to the logos, as well as a strange twist of unrequited love that is also somehow requited in the end.
A good, enjoyable read with some thought provoking questions raised and an unusual view of angels.