It was the gallerist Muriel Latow who came up with the ideas for both the soup cans and Warhol's dollar paintings. On November 23, 1961, Warhol wrote Latow a check for $50 which, according to the 2009 Warhol biography, "Pop, The Genius of Warhol", was payment for coming up with the idea of the soup cans as subject matter. For his first major exhibition, Warhol painted his famous cans of Campbell's soup, which he claimed to have had for lunch for most of his life. A 1964 "Large Campbell's Soup Can" was sold in a 2007 Sotheby's auction to a South American collector for £5.1 million ($7.4 million).