This dissertation examines the late-20th-century transformation of the art object through the practice of Fluxus, an international, neo-avant-garde artist collective founded in 1962 and centered in New York. Focus is given to three key figures: George Maciunas (Lithuanian-American, 1931-1978), George Brecht (American, 1926-2008), and Robert Filliou (French, 1926-1987). It traces chronologically these artists' development of three central Fluxus formats--the event score, Fluxbox multiple and Fluxshop--as they confronted established object categories pertaining to the mediums of music, painting, and sculpture; the emergent category of the multiple; and prevailing economic models of the commodity and the store/gallery.

Fluxus was informed by the aesthetics of music, in particular the work and teaching of experimental composer John Cage. Chapter 1 thus provides an historical analysis of graphic notation in the 1950s in order to fully articulate the implications of the score model taken up by Fluxus artists in 1958--here seen as the foundational "diagram" for the Fluxus object. Chapter 2, focused on Brecht, examines the interrelation between the artist's event scores and object practice centered on readymade objects, here newly defined as "notational objects." Chapter 3 turns to Maciunas's production of Fluxbox multiples and that format's relationship to the medium of sculpture, the emergent market for artist multiples, and 1960s commodity culture, elaborating a theory of the Fluxbox as "transitional commodity." Finally, Chapter 4 considers the aesthetic and political potential of Fluxus's "unworking" by the late 1960s through experimental forms of distribution and community-building modeled in the under-recognized work of Filliou.

The project thus moves from an articulation of the origins of Fluxus's unique object model to a theorization of how the group's "objects without object" (to borrow the title of a work by Filliou) amounted to a radical statement about postmodern subjectivity and community formation. It provides a new account of Fluxus and of a crucial moment within the paradigm shift in postwar artistic practice toward the conceptual, ephemeral, and performative art forms that have come to define the post-medium condition of postmodern and contemporary art.