A critical examination of the philosophical theories of Fritz Mauthner (1849-1923). Mauthner was a prolific writer with diverse intellectual interests, but he was preoccupied with developing a comprehensive philosophy or 'critique' of language which would help resolve a whole range of persistent and controversial philosophical problems. In pursuit of this aim Mauthner pioneered a view of language which has had a very wide circulation in the twentieth century - namely that the analysis and understanding of language, particularly ordinary language, is the philosophers most important task. Mauthner was very much an outsider from the German academic establishment and has little sympathy with the increasingly influential phenomenology of the time. In this thorough and authoritative study, Gershon Weiler locates his ideas in their proper historical tradition and urges that their originality now be recognised and their interest reconsidered.