This work is for comparative linguists and celticists who are keen to study Breton but may be too daunted to undertake such a venture by the wide variety of orthographical conventions which exist in Breton. The chronological development of the Breton orthographical debates during the twentieth century is charted along with an attempt to discern the ideological political and personal motivations which lay behind those debates. Based on a substantial corpus of hitherto unpublished original documents and personal interviews the research throws new light on the nature of the political ideological and linguistic divisions of the Breton movement of that period not least the events that occurred during the 193945 war.