A reductive sensibility pervades much of the avant-garde art of the 20th century. Spanning from its earliest decades to the new millennium, a radical aesthetics of formal clarity developed in tandem with the evolution of abstraction. During the 1920s, Piet Mondrian's omission of all extraneous details from his geometric paintings was prompted by a utopian impulse that equated purity of form with spiritual transcendence. In Russia, at roughly the same time, the Constructivists' eschewal of any decorative flourish associated with bourgeois taste represented a revolutionary disavowal of class-based connoisseurship and the Romantic notion of artistic subjectivity. At the heart of these movements toward an increasingly nonreferential, elemental form was the desire to create a new, universal aesthetic language. This reductivist impulse found renewed vigor during the 1950s in reaction to Abstract Expressionism, with its painterly excesses and invocations of individual unconscious states. Tony Smith's unadulterated geometric forms, Ellsworth Kelly's investigations of pure color and line, and Ad Reinhardt's meditations in shades of black served as critical counterpoints to the rhetorical gesture found in much Abstract Expressionist art. Robert Rauschenberg's multipaneled, all-white paintings from 1951 similarly rejected the heroics of Abstract Expressionism, their blank surfaces designed to register the shadows of their viewers and the temporality of the viewing experience. So impressed by the mute poetry of these iconoclastic canvases, the composer John Cage wrote his famous 4'33" (1952), an interval of absolute silence lasting as long as the title indicates. Rauschenberg's engagement with the flux of the environment in which the work was experienced and his recognition of the viewers' presence was enormously influential on a younger generation of sculptors and painters exploring art's materiality and its physical presence in the world. Along with the mechanical sensibility of Frank Stella's uniformly striped black paintings (begun in 1959), this work ushered in a decade of radical reductionism that came to be known as Minimalism. During the 1960s, a number of American artists, namely Carl Andre, Dan Flavin, Donald Judd, Sol LeWitt, and Robert Morris, endeavored to create an art that excluded all compositional complexity (including figure/ground relationships), all surface incident, and all referentiality. Primarily sculptural, Minimal art is premised on the elementalism of geometric forms. It rejects the handmade in favor of anonymous, industrial production. It foregrounds its own, essential objecthood, in place of any symbolic meaning. Seen in retrospect as the culmination and exhaustion of high Modernist values, which judged an artwork's validity by its adherence to the fundamental properties of its specific medium, Minimalism represents both an end and a beginning. It fulfilled Modernism's call for absolute self-reflexivity to a point of no return, paving the way for a younger generation of artists who would explore issues implicit in Minimalism's stripped-down aesthetic: an examination of the context in which art is encountered, an acknowledgment of the viewer's physical presence, and a revelation that art itself may function as a form of criticism. This exhibition, drawn largely from the Guggenheim Museum's permanent collection, is devoted to the minimalist impulse in contemporary art. The installation, which fills the museum's entire Frank Lloyd Wright–designed rotunda and adjacent Annex galleries 2, 5, and 7, examines the emergence of Minimalist art during the 1960s and its legacy during the ensuing decades. Singular Forms begins with a prologue establishing a postwar genealogy for Minimalism with a section dedicated to the reductivist paintings and sculpture of Kelly, Piero Manzoni, Rauschenberg, Reinhardt, Smith, and Stella. "Classic" Minimalism is represented by those most closely associated with the movement—Andre, Flavin, Judd, LeWitt, Robert Mangold, Brice Marden, Morris, and Robert Ryman, among others—as well as by those artists who shared in its aesthetic sensibility but not necessarily its ideology. These artists include Larry Bell, Agnes Martin, John McCracken, and Dorothea Rockburne, to name a few. Minimalism's impact on subsequent generations forms the next section of the exhibition. Post-Minimalism, a loosely defined aesthetic category, utilized the preceding movement's deliberate economy of formal means to explore a range of concerns including process, the dematerialization of the object, the performative nature of art, and the structural properties of light. Artist such as Jene Highstein, Robert Irwin, Richard Long, Bruce Nauman, Richard Serra, James Turrell, and Doug Wheeler are included in this section. Conceptual art also owes much of its self-reflexivity to Minimalism, in some cases due to a misreading of the movement as based purely on ideas. The exhibition features key examples of language-based art by Joseph Kosuth and Lawrence Weiner, which share in Minimalism's extreme reductionism, while underscoring its analytical dimensions. During the 1980s, many artists schooled in the deconstructive tendencies of postmodernism resuscitated Minimalism as a style, infusing its unitary, nonreferential forms with content to bring to the fore trenchant cultural issues. In the mid-1980s, Peter Halley, Sherrie Levine, and Allan McCollum deliberately appropriated the look of Minimalist painting to critique how systems of power, consumption, and desire are embedded in and perpetrated by representational codes. Felix Gonzalez-Torres appropriated the Minimalist cube for the formal source of his pristine, endlessly replaceable stacks of printed paper, which speak against social injustices such as homophobia and racism. Roni Horn's "pair objects"—twinned, geometric sculptures—explicitly activate memory and perception while invoking ideas about identity and difference. Charles Ray playfully evokes the heroic, industrial (and often macho) aspects of Minimalism with his reductivist sculptures that rely as much on illusion as volume and form. Robert Gober utilizes formal simplification to deeply poetic ends in his beautiful, hand-crafted versions of industrial objects—ghostly, nonfunctioning sinks, a sheet of plywood, and cast Styrofoam. Meg Webster creates pure, geometric forms out of organic materials such as salt, peat moss, and branches, to comment on the ever-increasing fragility of our ecosystem. And Glenn Ligon's coal black, nearly monochrome paintings veil texts under layers of pigment that articulate a specifically African-American experience. These are just a few examples of the ways artists today work with a reductive sensibility while sustaining a commitment to narrative, social engagement, and cultural commentary.