In June 1983 Margaret Thatcher won the biggest increase in a government's Parliamentary majority in British electoral history. Over the next four years, as Charles Moore relates in this central volume of his uniquely authoritative biography, Britain's first woman prime minister changed the course of her country's history and that of the world, often by sheer force of will.

The book reveals as never before how she faced down the Miners' Strike, transformed relations with Europe, privatized the commanding heights of British industry and continued the reinvigoration of the British economy. It describes her role on the world stage with dramatic immediacy, identifying Mikhail Gorbachev as 'a man to do business with' before he became leader of the Soviet Union, and then persistently pushing him and Ronald Reagan, her great ideological soulmate, to order world affairs according to her vision. For the only time since Churchill, she ensured that Britain had a central place in dealings between the superpowers.

But even at her zenith she was beset by difficulties. The beloved Reagan two-timed her during the US invasion of Grenada. She lost the minister to whom she was personally closest to scandal and almost had to resign as a result of the Westland affair. She found herself isolated within her own government over Europe. She was at odds with the Queen over the Commonwealth and South Africa. She bullied senior colleagues and she set in motion the poll tax. Both these last would later return to wound her, fatally.

In all this, Charles Moore has had unprecedented access to all Mrs Thatcher's private and government papers. The participants in the events described have been so frank in interview that we feel we are eavesdropping on their conversations as they pass. We look over Mrs Thatcher's shoulder as she vigorously annotates documents, so seeing her views on many particular issues in detail, and we understand for the first time how closely she relied on a handful of trusted advisors to help shape her views and carry out her will. We see her as a public performer, an often anxious mother, a workaholic and the first woman in western democratic history who truly came to dominate her country in her time.

In the early hours of 12 October 1984, during the Conservative party conference in Brighton, the IRA attempted to assassinate her. She carried on within hours to give her leader's speech at the conference (and later went on to sign the Anglo-Irish agreement). One of her many left-wing critics, watching her that day, said 'I don't approve of her as Prime Minister, but by God she's a great tank commander.' This titanic figure, with all her capacities and all her flaws, storms from these pages as from no other book.