Marilyn Monroe would have celebrated her 100th birthday this year. My new biography of her begins with this story: she’s walking with a friend down Park Avenue dressed in a raincoat and sunglasses and without make-up. As the crowds stream past her, nobody gives her a second glance. Then she turns to her friend and asks, “Do you want to see me be her?” Without changing her hair or dress, the transformation begins and, after making some kind of inner psychological adjustment, she morphs from an ordinary woman into Marilyn Monroe, superstar. As her friend, the actress Susan Strasberg, recalled: “There she was – not the simple girl I’d been strolling with, but ‘Marilyn Monroe,’ resplendent, ready for her public. Now heads turned. People crowded around her.