What accounts for the astounding rise in fortunes of Marlene Dumas? Her work currently holds the record for highest-selling work by a living woman artist. “In 2002, the record for Ms. Dumas’s paintings, only a few of which had come to auction, stood at about $50,000. Yet last month at Christie’s in London, after a bidding war between two dealers, her 1987 painting “The Teacher,” a rendering of a posed class photograph, went for a startling $3.34 million.”