Thatcher set about upending decades of liberal doctrine, successfully challenging Britain's welfare state and socialist traditions, in the process becoming the reviled bete noire of the country's leftwing intelligentsia.
She is perhaps best remembered for her hardline position during the pivotal strike in 1984 and 1985 when she faced down coal miners in an ultimately successful bid to break the power of Britain's unions. It was a reshaping of the British economic and political landscape that endures to this day.
It is for this that she is revered by free-market conservatives, who say the restructuring of the economy led to a boom that made London the rival of New York as a global financial center. The left demonized her as an implacably hostile union buster, with stone-cold indifference to the poor. But her economic philosophy eventually crossed party lines: Tony Blair led a revamped Labour Party to victory by adopting some of her ideas.
Margaret Hilda Roberts was born on Oct. 13, 1925. She learned the values of thrift, discipline and industry as the dutiful daughter of Alfred Roberts, a grocer and Methodist lay preacher who eventually became the mayor of Grantham, a modest-sized town in Lincolnshire 110 miles (180 kilometers) north of London.
Thatcher's personality, like that of so many of her contemporaries, was shaped in part by the traumatic events during her childhood. When World War II broke out, her hometown was one of the early targets for Luftwaffe bombs. Her belief in the need to stand up to aggressors was rooted in the failure of Prime Minister Neville Chamberlain's attempt to appease Adolf Hitler rather than confront him.
Thatcher said she learned much about the world simply by studying her father's business. She grew up in the family's apartment just above the shop.