Critical writing on public art in the late 20th century in the UK and USA either legitimized public art as an extension of studio art intended to widen its public, or implied a new relation to public space - as demonstrated in texts by Cork (1995) and Phillips (1988) respectively. This suggests a polarization of art's aesthetic and social dimensions. A deeper understanding of the relation between these dimensions is found in the work of Marcuse, Bloch and Adorno. Marcuse, in his early work, sees art as serving the needs of bourgeois society by displacing ideas of a better world to an independent aesthetic realm; Bloch sees art as giving form to hope, shaping a recurrent aspiration for a better world; Adorno sees the tension between the aesthetic and social dimensions of art as unresolvable, and, like Marcuse in his later work, sees art's autonomy as a space of criticality. But, as Bloch argues, conditions for change are noncontemporaneous, fostering culture which is both progressive and regressive. In this respect, Gablik's appropriations of other cultures may be seen as regressive, whilst Lippard's concern for locality offers art a basis for progressive intervention. The introduction of the local, as a point of reference alongside the aesthetic and social, leads to consideration of three cases of art practice: Common Ground's Parish Maps (1986-96), the Visions of Utopia Festival coordinated by the Artists Agency (1996-8), and 90% Crude (1996--), a project by PLATFORM in London. The originality of the thesis is in its investigation of these cases; and equally in making connections between them and the elements of art criticism and critical theory noted above.