It will also be a moment of celebration for the three or four people who most helped her.
The foremost assistant was Robin Harris, the donnish intellectual who was head of the Conservative Research Department and a senior figure in her No 10 policy unit. He played a central part in the fast turnround of the book from its inception in October 1991 to June 1993.
Lady Thatcher preferred to talk into a tape recorder, and she was also able to rely on private and contemporary aides memoire she had dictated on the Falklands war. They were furnished by a stream of memos from Chris Collins, a young Oxford researcher, for example on other accounts of the Thatcher years.
But another key figure was John O'Sullivan, a leading Thatcherite journalist who edits the National Review in Washington and was once a Daily Telegraph parliamentary sketchwriter. He worked with Harris on both the second and third drafts, gently persuading Lady Thatcher to shed the official reticence natural in a Prime Minister of 12 years, be more candid, and put more light and shade into her account. Some of the book was written in Lady Thatcher's home in Belgravia, central London, but also partly in intensive sessions away from London on retreats in places as far afield as Gstaad, and on one occasion, the Bahamas.
She was able to pore over all the secret Cabinet papers - to which she has access as of right. But another key piece in the jigsaw was a series of tape-recorded sessions with Sir Charles Powell, her former principal private secretary.
And there were the now famous 'anecdote lunches' with Sir Denis and Lady Thatcher and a vigilant shorthand writer. One guest, Sir Bernard Ingham, Lady Thatcher's former press secretary, recalled: 'We had a drink, sat down to lunch and anecdoted away like mad. A good time was had by all and I got my train home.' One story Sir Bernard recalled was how she asked to see a teddy bear presented to him on his birthday by reporters on a trip to Canada and how she had protested that the bear 'should have some rompers'.
However, this sort of anecdote is unlikely to be the stuff of the book. The publisher certainly put pressure on her to spice it up, but she told a friend early on that she wanted to stick to 'the issues' rather than personalities.
The friend added: 'I wouldn't say she enjoyed doing it exactly. It was more like a mission. She was driven. And her energy makes her a publisher's dream.' She also, unlike several of her former colleagues, submitted the manuscript to the Cabinet Office and avoiding detailed discussion of the role of civil servants.
Another important part was played by Stuart Proffitt, the Harper Collins editor assigned to her. In a gushing interview with Publishers' News this week, he speaks of her 'elephantine memory' and says that while there was little time for small talk on the night of the disappearance of the publisher Robert Maxwell she poured drinks and they sat watching the television news. They also talked about the philosophers Locke and Hobbes and recited Tennyson together. 'She knows great chunks of 19th-century English poetry by heart,' he said.