John Barth is one of the major novelists of American postmodernism. Barth’s contribution to the practice and theory of postmodernism is in this sense undisputable. However, much of the criticism dealing with his work in relationship to postmodernism is prompted by Barth’s own theories of “exhaustion” and “replenishment,” leaving his writing relatively untouched by theories of postmodernism in general. This study aims to change that. What is of particular interest here is the relationship between Barth’s aesthetic and the ideology critical work of the historical avant-gardes, which were the first to mobilize art against itself and its institutional practices and demands. This mobilization often took the form of an intentional shattering of the boundary between life and art and a subsequent critique of notions such as originality and organicity. To emphasize the idea of literature as practice (life), I focus on the notion of spatiality as it is defined and conceptualized within Marxism and Critical Theory, particularly by Fredric Jameson, Jean Baudrillard, Guy Debord, and Johannes Fabian. As many of these discussions show, spatiality is connected to human consciousness and material reproduction, generating not only the subject-object distinction, but also notions of temporality, historicity, and causality. There is, however, a paradox involved in the production of space. On the one hand, space can only be generated through systems of representation; on the other, our notion of reality requires space to be lived and authentic. The ability to produce space is therefore always connected to metaphorical skills. Yet, space exists only as social practice, as a field of authenticity. In this context, travel is seen as one of the fundamental spatial practices with which such a literalization is made. Examining Barth’s metafictional parodies in the light of these theories of space and subjectivity, I try to engage the question of ideology critique in postmodernism. My first chapter focuses on the postmodernism debate in America towards the 1990s, where I give a general historical overview of the issues discussed and elaborate connections to various theories and strategies of the historical avant-gardes. Next, I introduce the concept of spatiality, which has become the central issue defining postmodernism. Spatiality is generally seen as weakening of historicity and temporality, and by extension, of reality itself. I try to dispute this idea and relate the “spatialization of time” occurring within postmodernism to ideas of critical art. Thirdly, I explore the relationship of travel to the production of space. Here I suggest that travel above all is an acculturation of the real, a spatial practice through which reality acquires a meaningful and coherent structure. Chapter Two focuses on how these issues of spatiality, travel, and representation work their way into the fiction and essays of John Barth. The last chapter is a close reading of one of Barth’s later novels, The Last Voyage of Somebody the Sailor (1991), which aims to bring the previous discussions into proximity with one specific text. Here I argue that the montage can offer a critical model for understanding the spatiality of postmodernism, particularly its “simultaneity of the radically disparate.” My discussion ends by suggesting that such a take on postmodernism may well be perceived as a mimesis of reality, particularly a recognition of the collective nature of self and world.