Alberto Giacometti (1901–1966). Bust of a Man, plaster, 1965. When Giacometti left Paris on December 5, 1965, his brother Diego offered to make a mould of his latest statue in order to cast a bronze from it. “No,” Alberto told him, “it is not finished yet. I must do some more work on it.”

Alberto Giacometti (1901–1966). Bust of a Man, plaster, 1965. When Giacometti left Paris on December 5, 1965, his brother Diego offered to make a mould of his latest statue in order to cast a bronze from it. “No,” Alberto told him, “it is not finished yet. I must do some more work on it.”

Ana Mendieta (1948–1985). Untitled, 1985. Semi-circular tree trunk carved and burnt with gunpowder, for a proposed project for the MacArthur Park Public Art Program in Los Angeles, which was not completed before her death.

Ana Mendieta (1948–1985). Untitled, 1985. Semi-circular tree trunk carved and burnt with gunpowder, for a proposed project for the MacArthur Park Public Art Program in Los Angeles, which was not completed before her death.

Wassily Kandinsky (1866–1944). Unfinished painting, 1944.

Wassily Kandinsky (1866–1944). Unfinished painting, 1944.

Piet Mondrian (1872–1944). Victory Boogie Woogie, 1944. “Three days before he was taken to the hospital he had begun a drastic revision of his latest painting which was practically ready for exhibition and to which he had already given more than nine months constant work.” –Art Chronicle, 1944

Piet Mondrian (1872–1944). Victory Boogie Woogie, 1944. “Three days before he was taken to the hospital he had begun a drastic revision of his latest painting which was practically ready for exhibition and to which he had already given more than nine months constant work.” –Art Chronicle, 1944

Marcel Duchamp (1887–1968). Cheminée anaglyphe, 1968. A 3D stereoscopic (anaglyph) drawing of a chimney.

Marcel Duchamp (1887–1968). Cheminée anaglyphe, 1968. A 3D stereoscopic (anaglyph) drawing of a chimney.

Felix Gonzalez-Torres (1957–1996). No title, 1995. Billboard image.

Felix Gonzalez-Torres (1957–1996). No title, 1995. Billboard image.

Joseph Beuys (1921–1986). I Hereby Resign from Art, 1985. From a set of postcards.

Joseph Beuys (1921–1986). I Hereby Resign from Art, 1985. From a set of postcards.

Mark Rothko (1903–1970). Untitled, 1970. Rothko returned to using color for his final three paintings after two years of painting in only blacks, grays, and browns.

Mark Rothko (1903–1970). Untitled, 1970. Rothko returned to using color for his final three paintings after two years of painting in only blacks, grays, and browns.

Gordon Matta-Clark (1943–1978). Immunes Versus Cancer, 1978.

Gordon Matta-Clark (1943–1978). Immunes Versus Cancer, 1978.

Egon Schiele (1890–1918). Edith Schiele (on her deathbed), October 28, 1918. Egon made two drawings of his wife Edith on her deathbed. She succumbed to Spanish Flu, as did the artist three days later.

Egon Schiele (1890–1918). Edith Schiele (on her deathbed), October 28, 1918. Egon made two drawings of his wife Edith on her deathbed. She succumbed to Spanish Flu, as did the artist three days later.