Richard Avedon, 1957. The most psychologically revealing Marilyn portrait in existence.
From Wikipedia
Marilyn Monroe was an American actress and model. Known for playing comic "Blonde bombshell" characters, she became one of the most popular sex symbols of the 1950s and early 1960s, as well as an emblem of the era's sexual revolution. She was a top-billed actress for a decade, and her films grossed $200 million by her death in 1962.