Blasphemy is one of those peculiar ways of thinking found in the beginnings of recorded history. It has consistently killed more people and blighted more lives than anything else in the history of the various known worlds. Cities, towns, villages and houses have been reduced to rubble, and arable land has been rendered infertile. It is structured in the form of a circle with various segments. In the centre stands belief, sometime religious, sometimes secular, and sometimes a peculiar blend of the two which may alternate in terms of dominance. The case studies are from Catholicism and Communism. The book started out life as class notes in Dublin City University in the 1980s, but the content has been revisited and revised, and now also serves as an overview of how Catholicism and Communism have changed radically in the last thirty years.