Today - November 12 - is the 30 anniversary of the release of Madonna's second album, Like a Virgin. Thirty years - digest that for a moment. If you're shrugging and asking "What's to digest?", you're probably under 30 and have never known a world without Madonna - you don't know how different life was for young women before she became a lightning rod for debate on Western female sexuality, and changed the way women view sex, love and ambition.
If her only achievement had been to expand what was considered possible for women in pop music, she still would have been remarkable. Her influence is felt so far beyond pop, however, that she even inspired a strand of academia known as Madonna Studies, which examined her effect on sexuality and feminism. She's sold 300 million records - more than any other female singer - and may be the only pop star to have generated a new word, "wannabe" - coined in the '80s, when the aspirations of every teenage girl were summed up by the phrase "I wannabe Madonna". Though not a conventionally gifted singer, she's pushed through every barrier that stood between her and success, showing what can be accomplished by unyielding determination and a gift for being one step ahead of the zeitgeist. During her golden years - 1983 - 89, say - she was the zeitgeist.
Around 10 years ago, she was asked by an interviewer how she thought she was seen by the public. "I guess I'm known for being disciplined," she replied, but she could also have said "controlling", "independent" and "tough" - traits female singers weren't supposed to possess, at least not openly, when she started out. It's now routine for women musicians to call the shots in their careers - or to claim they do - but when Like a Virgin appeared, her insistence on making her own decisions was unique.
It was the album that made her commercially and culturally unstoppable. The cover photo of Madonna acting out the virgin/whore dichotomy by wearing a wedding dress and a belt that spelled out "Boy Toy" was only the start. The album's title track - which spent six weeks at the top of the American chart - went where no pop single had gone before, equating the experience of falling in love to being sexually untouched. No other female singer had ever shoehorned the subject virginity into a pop song so bluntly, or made it clear that no matter what you were - virgin or sexually experienced - it was absolutely fine.
One of the album's other massive hits, Material Girl, was about her being motivated by money rather than love (which greatly riled middle american parents, as did almost everything about her). The song was a typical mix of bluntness and coquettish sweetness - boys were okay, the song said, but the one she really wanted was "the boy with the cold hard cash."
From the start, she knew exactly what buttons to push to be the centre of outraged attention. While writing a new biography of her, Madonna: Ambition. Music. Style, I was struck by the rage she incited in the '80s: the religious right hated her for saying she found crucifixes sexy because there was a naked man on them; feminists were angered by the Boy Toy belt and others were concerned by her blithe habit of cultural appropriation.
She also lost an endorsement deal with Pepsi by dancing in front of burning crosses and kissing a black Jesus in the video for Like a Prayer. At times, her main occupation seemed to be breaking taboos - "If you want to be a whore, it's your fucking right to be so" was a typical edict, one of many that encouraged women to celebrate and control their sexuality.
Her own celebration of her unquenchable appetites peaked with the 1992 book Sex, which featured explicit photos of her and male and female partners. To her undoubted delight, many bookshops refused to stock it. "Is it degrading to women? Well, sure, and to men, too," said the New York Times. Naturally, that didn't stop it selling 1.5 million copies.
Thirty years later, she's not going gentle into that good night.
Madonna: Ambition, Music, Style is published by Carlton and out now.