While we are confident that the bulk of material in Mandela’s private archive was scrutinised by the team, not everything in the custody of private individuals was located and made available to us. It was by chance, for example, that in the final months we stumbled across the archive kept by former warder Jack Swart, who was with Mandela during the last fourteen months of his incarceration in Victor Verster Prison. Also late in the game, the National Intelligence Agency disclosed to us the existence of a small Mandela collection, most of which was made available to the team. The Agency’s caginess suggests the possibility of further disclosures.

While all of the Mandela private archive was considered for this project, the final selection drew most heavily on four particular parts. Firstly: the prison letters. Some of the most poignant and painful writings are to be found in two hard-covered exercise books in which Mandela carefully drafted copies of letters he subsequently sent through the prison censors on Robben Island. They date from 1969 to 1971 and cover the very worst time of his imprisonment. Stolen from his cell by the authorities in 1971, they were returned to him by a former security policeman in 2004. Throughout his time in prison Mandela was never sure whether his correspondence would reach its destination due to the actions of what he called ‘those remorseless fates’, the censors. His prison files in the National Archives contain numerous letters the authorities wouldn’t post. They are kept together with copies they made of every letter that they did post.

Secondly: two major collections of taped conversations. Here, the spoken voice, not the written word, is heard. These encounters are so intimate, so informal, that Mandela frequently moves into reverie, enters into a dialogue with himself. The first set is about fifty hours of conversations with Richard Stengel, made when the two men were working together on Long Walk to Freedom. The second is a set of about twenty hours of conversations with Ahmed Kathrada, who was sentenced with Mandela and six others to life imprisonment on 12 June 1964. Kathrada was asked in the early 1990s to assist Mandela in reviewing the draft texts of both Long Walk to Freedom and Anthony Sampson’s authorised biography. The behind-the-scenes interaction of these two old comrades is relaxed. They are often chuckling or laughing out loud. The conversations are interesting not only for what Mandela says, but for how he says it.

Thirdly: the notebooks. Before his imprisonment in 1962, it was a habit of Mandela’s to carry a notebook. He had one with him during his journey through Africa (and to England) in 1962 to learn about revolutionary strategies, to be trained in guerrilla warfare, and to secure support from leaders of newly independent countries and nationalist movements. He had one with him when he was captured shortly after his return to South Africa. He resumed this practice in the years after his release from prison, when he was negotiating South Africa’s transition to democracy, and even, to some extent, during his presidency. These later notebooks contain notes to self, aide-mémoire, records of meetings and drafts of letters. There are also several extraordinary chunks of writing, each of many pages (not reproduced here for reasons of space and narrow interest), from meetings of the African National Congress Working Committee, during which he meticulously recorded the points each speaker made. Why he did this is not entirely clear. Probably it was a lawyer’s habit of carefully taking down information from his clients. Perhaps, at over seventy years of age, he felt he could not entirely trust his memory.

And fourthly: the draft of an unfinished sequel to Long Walk to Freedom. On 16 October 1998, he took a piece of blue notepaper and with a favoured pen he put down, in a strong and decisive hand, the date in Roman numerals. He followed this with what was his working title: ‘The Presidential Years’.