The Parafaith War (1996) is a science fiction novel by American writer L. E. Modesitt, Jr. It is set in a future where humanity has spread to the stars and divided into several factions. Two factions, the Eco-Tech Coalition and the Revenants of the Prophet ("revs") are engaged in a futile war over territory and their competing social philosophies. The ecologically-aware Coalition must hold back the zealous rev hordes constantly seeking new territory for their ever-expanding theocratic society. Source: Wikipedia (en)