Fascism is discussed as a pathology of masses under capitalism, and its components are defined.  It was a class block between rulers and segments of the middle classes while neutralising the working classes and any deviant political forces by terror and ideology. Ultra-nationalism is presented as its key element, and minimum preconditions identified. Economics and class regrouping, as well as profiting and hegemony in fascist states are stressed. A section approaches clerical fascism, and incidentally “Eastern Europe”.  A brief Conclusion looks at current “Fascism 2.0”. A lengthy select chronological bibliography on fascism with annotations is appended.