This is Joseph Cornell's handwritten account of a dream he had about Marcel Duchamp, from 1968. In the dream, Cornell told Duchamp that Delacroix was visiting New York City, but Duchamp didn't believe him. Cornell then said that Delacroix was putting up at a Parisian hotel, and at that point, Duchamp believed—and decided he wanted to get one of Delacroix's handkerchiefs from him.

Cornell's diary entry is part of a surprisingly rich temporary exhibition at the National Portrait Gallery called Inventing Marcel Duchamp: The Dynamics of Portraiture. It's up until August 2 and includes more than 100 portraits of the infamous chess player, cross-dresser, and readymade-maker, both by the artist and by other artists, from the early American modernist painter Florine Stettheimer to Warhol, who made a Screen Test of Duchamp shown here on video. Most of Warhol's test subjects were still, or uncomfortable, but Duchamp winks, smokes, smiles, drinks a glass of water, and seems to relate to people offscreen. He owns the joint.

The old favorites are all here (Rrose Selavy, the Monte Carlo soap horns, Baroness Elsa's feather sculpture of Marcel, Duchamp's Wanted posters, the Man Ray and Alfred Stieglitz portraits, the double exposures, Jean Crotti's wire cartoon, Brian O'Doherty's actual cardiogram of Duchamp's heartbeat).

Two new favorites: David Hammons's The Holy Bible: Old Testament, from 2002, a finely bound readymade holy book: a reprinting of Arturo Schwarz's catalog raisonné of Duchamp's works. And Frederick Kiesler's 1947 eight-part pencil drawing of Duchamp from life. The artist is wearing a tie but no shirt. His head is huge, his feet small. Each body part is drawn on its own paper, and together, they are all mounted in a large wooden frame about the dimensions of Duchamp's Large Glass. (I wish MoMA, which owns it, had an image up.)