The Jewish community in Britain has been characterised by its high degree of conformity. This study seeks to extend the parameters of Jewish life by including those hitherto excluded from the historical narrative so that the community can more effectively be viewed as a paradigm for understanding the challenges facing minority communities in their encounter with mainstream society. It sets Jewish involvement within the wider historical, social, economic, political and cultural context, in which it developed, focusing upon political radicalism in Manchester, 1889-1939, and Jewish participation in radical socialism, anarchism, bundism and communism. Nonconformity is here defined in terms of a distancing from both external pressures (e.g. social conformity with the wider community) and internal pressures (e.g. religious beliefs and concerns about communal image). Through the prism of Manchester the chapters will highlight debates surrounding the makeup and impact of pre-First World War involvement; the disproportionate involvement of Jews in radicalism; the nature of Jewish allegiance to communism as an ideological conversion or a convergence of interest and the impact of involvement on Jewish identity, described as 'Jewish communists' or 'communist Jews'.The thesis draws upon new information from the radical Yiddish and English press, revealing the importance of English and foreign influences on pre-war radicalism. Its use of oral testimonies at the Manchester Jewish Museum and elsewhere has revealed in the post-war period, a layering of motivation, commitment and identity. Written chronologically, the periodization of this study enables connections and differences to be drawn. It shows significant discontinuity in involvement and influence between pre and post-First World War radical activity, unlike in London. In Manchester those drawn to communism post-war were almost entirely from an English-born generation. They were more representative of the communist Jew, whose communist identity superseded but did not eradicate their Jewish identity. The thesis shows that conversion to communism was not due to any inherent ethnic characteristics. From 1920-1932 it was a response to the same social and economic factors which influenced non-Jews to communism, but encased in a cultural and historical context. From 1933 that process of conversion continued but was greatly boosted by the desire to fight fascism. The communist led fight against fascism and provision of a popular youth club acted as an attraction to youngsters, who were subsequently influenced in differing degrees or not at all by Marxism. This resulted in different levels of commitment and identification, some of which continued after the war, resulting in the formation of a subculture of Marxist and secular left-wing Jews, who are still seen as nonconformists by the mainstream Jewish community.