The aim of this thesis is to relocate the work of somelate nineteenth-century British writers, including Walter Pater,Oscar Wilde and William Morris, within the history of the avantgarde.This is carried out in two ways. First, I examine andcriticize on both theoretical and methodological grounds,current theories of the avant-garde, focusing particularly onthe work of Renato Poggioli and Peter Burger. In their place Ioutline a new theory, based on some premisses derived fromthe philosophy of intellectual history, which attempts toestablish the intellectual conditions which make avant-gardeactivities possible. In this new theory I argue that the politicsof avant-garde movements are culturally and historicallyspecific. I then use this theory to establish the conditions foravant-garde activity in late nineteenth-century Britain. Thisundertaking involves an examination of general intellectualdevelopments which took place in Britain in the last quarter ofthe nineteenth century; more precisely, it entails describingthe intellectual changes which took place in political economy,historiography and sociology, for I suggest that these changes,by problematizing concepts of society and of history, both madeBritish avant-garde activity possible, and determined the formsit took. The second part of this thesis examines the work ofthe above mentioned writers - Pater, Morris and Wilde - in the context of these wider intellectual and cultural changes. Isuggest that the subversive political implications - and hencethe avant-gardism - of their work may only be properlyassessed in such a context.