Exploring the nature of the aesthetic medium has been at the heart of much of modern art. For exponents of high modernism, following the lead of Clement Greenberg, the essence of each medium - what made it specific - lay inherently in its own particular material properties. Accordingly, the import of painting was its "flatness," as exemplified by the monochrome canvas - painting so reduced that nothing is left but a mere flat object. But some artists rejected this reductivist description of the aesthetic medium as inadequate. Citing the examples of film, television and video, they understood and articulated the medium as aggregative, as a complex structure of interlocking and interdependent technical supports and layered conventions distinct from physical properties. For them, the specificity of a medium lay in its constitutive hererogeneity - the fact that it always differs from itself. Here, Rosalind Krauss positions the work of Marcel Broodthaers within this alternative narrative. Referring to the Belgian artist's films, books, graphic design and museum "fictions," she presents Broodthaers as standing at, and thus standing for, the "complex" of the self-differing medium. Professor Krauss argues that his work demonstrates that the specificity of mediums, even modernist ones, can never be simply collapsed into the physicality of their support.