"Marcel Duchamp, one of this century's pioneer artists, moved his work through the retinal boundaries which had been established with impressionism into t field with impressionism into t field where language, thought and vision act upon one another, There it changed form through a complex interplay of new mental and physical materials, heralding many of the technical, mental and visual details to be found in more recent art...In the 1920s Duchamp gave up, quit painting. He allowed, perhaps encouraged, the attendant mythology. One thought of his decision, his willing this stopping. Yet on one...