[6] Her mother, Hortense Kalisher Kleinberg, was a commercial artist and a fierce proponent of women's rights who influenced her daughter's views on independence.

[8] Baer's work of the late 1950s explored visual elements that paralleled members of the New York School, particularly Arshile Gorky, Robert Motherwell, Clyfford Still, and Mark Rothko.

[9][7] The Koreans were composed of a dominant field of densely painted white enclosed by bands of sky blue and black that seem to shimmer and move: this optical illusion underscored Baer's focus on "the notion of light.

Baer summed up the artistic concerns of her own work in 1971, writing, "Non-objective painting's language is rooted, nowadays, in edges and boundaries, contours and gradients, brightness, darkness and color reflections.

"[11] Baer was accepted as a peer in the burgeoning Minimalist movement by such artists as Sol LeWitt, Donald Judd, and Dan Flavin.

[6] He included Baer,[13] along with Judd, Flavin, LeWitt, Ward Jackson, Frank Stella, Irwin Fleminger, Larry Poons, Walter Darby Bannard, Robert Ryman, Leo Valledor, and himself.

That year she was also represented in both "Systemic Painting," a survey exhibition of contemporary geometric abstraction at the Solomon R. Guggenheim Museum in New York City.

Besides Baer, Reinhardt, and Smithson, the other artists selected were Carl Andre, Judd, LeWitt, Flavin, Robert Morris, Michael Steiner, and Agnes Martin.

[15] Baer's works shown in these exhibitions, which included vertical and horizontal single, diptych, and triptych paintings, established her avant-garde reputation in the New York art world.

"[16] Further challenging the notion of where a painting begins or ends, Baer added sweeping diagonal and curved paths of color that streaked across her once-inviolate white fields and down the sides of the canvas.

[19] Because she publicly questioned the tenets of a powerful pantheon of artists that included Judd and Morris, Baer was ostracized by a number of her former colleagues.

Baer needed a distance from New York's art world, and in June 1975, she moved to Smarmore Castle, a manor and working farm with a Norman keep, in County Louth, Ireland.

Baer also drew on erotic images found in early cave paintings, Paleolithic sculptures, and fertility objects to create compositions that suggested palimpsests.

[22] While in London, Baer wrote one of her best-known articles, "I am no longer an abstract artist," a manifesto published in Art in America in October 1983.

[23] Baer chronicled "abstraction's demise," and in characterizing its meaninglessness in a vastly changed world, claimed openness, ambiguity, "metaphor, symbolism, and hierarchical relationships" as necessary building blocks of modern works.

Disparate images and symbols from American, European, Asian, and classical civilizations are fused with quotations from literature and densely layered allusions to the themes of war, sexuality, the destruction of the natural world, greed, injustice, repression, transience, and death.

Subsequent surveys of her work have been organized by The Paley Levy Gallery at Moore College of Art and Design, Philadelphia (1993); Kröller-Müller Museum, Otterlo (1993); Stedelijk Museum, Amsterdam (1999); Dia Center for the Arts, New York (2002–2003); Van Abbemuseum in Eindhoven, (1986 and 2009); Galerie Barbara Thumm, Berlin (2010); and Gagosian Gallery, Geneva (2012).

[32][33] Baer wrote a number of texts over the years, these are brought together in Broadsides & Belles Lettres Selected Writings and Interviews 1965–2010,[34] which provide a general commentary on art as well as her own attitude to her work.