It would be one of history's more splendid ironies if, as this engrossing biography persuasively suggests, the CIA played a major role in the emergence of successful opposition to apartheid in South Africa, and the rise of Nelson Mandela to his position of extraordinary moral and political authority.
The irony resides in the fact that the CIA's intention was, of course, precisely the opposite. The CIA, Sampson believes, may well have been the source of the intelligence information which allowed two South African policemen to pick up Mandela not long after his return from abroad in 1962, leading to his prolonged imprisonment on Robben Island.
If, as Sampson believes, the CIA fingered Mandela, it was because that organisation was deeply apprehensive about the ANC, and even more frightened of its junior partner, the South African Communist Party. The CIA's estimation of the threat posed by the SACP was erroneous (it became known as the "Sheepish About Communism Party"), and the Americans also misunderstood the nature and political viability of the ANC. But the CIA's eagerness to help South Africa's white masters by assisting in the capture of Mandela also led to that extraordinary period of maturation and political development that marked his incarceration; it may also have indirectly saved him from probable assassination, the fate of so many ANC activists at the hands of the security forces' death squads in the later 1960s or early 1970s.
Sampson was not just an inspired choice for this authorised biography; in a sense, he was the only one. He has had a love affair with Africa for many years, and among the source materials he was able to draw on were his own unpublished diaries, stretching back almost half a century. His writing, which has an Orwellian clarity and stylishness, is embedded in that literate, urbane, fair-minded tradition of the Observer, which was for years the ideal of many aspirant young journalists, and may yet be so again. He has had unparalleled access to private papers and to key interviewees - much more so than Martin Meredith, whose valuable but more limited book was published in 1997 - and has produced an absorbing, revealing study of a man whose life and career have major significance in a world in which racism, far from having been extinguished, is on the increase.
As a work of biography, it has deep strengths. It identifies political mistakes that Mandela made, and underlines some of the psychological traits which have at times militated against him attaining his objectives. It goes as far as is decently possibly into the emotional torture chamber of Mandela's later relationship with Winnie, and with his adult children. At the end, we are left with the feeling that, insofar as it is possible to know any man by reading words on a page, we know Mandela with something approaching intimacy. He is, Sampson suggests, "not so much postmodern as pre-modern", a thorough-going radical democrat who also remained, at some essential level, the son of a chief. Perhaps it was precisely this mixture which helped to give him his unique sway over his people.
It is also invaluable on a more structural level. Sampson's account of the three-cornered manoeuvring involving de Klerk, Buthelezi and Mandela explores de Klerk's tactics, in particular, with a scalpel, and illustrates not just the dogged tenacity, but the skill with which white South Africa fought its corner, almost down to the last. It is good, too, on the effectiveness of the regime's links with its governmental supporters in other countries, and on the blinkered approach by the diplomatic missions of so many of these countries to the emerging, unstoppable political forces represented by the ANC.
There are one or two instances in which something vaguely unpalatable or unexplained is finessed. Sampson, for instance, dismisses as "without evidence" the allegation that Oliver Tambo, possibly on Mandela's behalf, had one of Winnie's victims spirited away to Zambia so that he could not testify against her. But Fred Bridgland's recent hypercritical, even tendentious, book on this topic is not entirely without evidence, even though it is hearsay evidence. The source of the suggestion is not Bridgland himself but Kenneth Kaunda, who is still alive.
Elsewhere, Sampson notes that Mandela "appeared to tolerate inefficiencies and abuses of power" because his priority was building up a new nation. But inefficiency and abuse of power are not problems of the same order of magnitude, and a new nation which condones abuses of power for any reason is ignoring some particularly rank weeds in its garden. Indeed, Sampson's observation that Mandela in 1997 was "personally often shocked by the new mood of financial ambition and the careerism of the younger political generation", reminds us that Sean Lemass was worried about the same sort of development within his own national movement some fifteen years earlier, even though he was considerably more circumspect about voicing his concerns.
In this sense, Sampson's study of the tensions and strains within the ANC and its allies provides us with an invaluable template for assessing movements in other countries, especially where those movements involve both military and political activity. Sinn Fein and the IRA are just such a movement and, although I would reject the view that Sinn Fein's struggle and that of the ANC have been in any meaningful sense analogous, it is difficult to suppress a wry grimace at de Klerk's outburst, during the negotiations with Mandela, that unless the issue of arms was resolved "we will have a party with a pen in one hand claiming the right to have arms with the other."
Mandela's ability to incorporate and maintain links with the ANC militants, even as he increasingly disagreed with their prognosis and their tactics, marks him as a leader of extraordinary subtlety and skill. And this story of his life suggests to us that, even though the situations there and here are radically different, South Africa may yet have something to teach us all about reconciliation and about the channelling of white-hot political nationalism into the mould of peace.
John Horgan is Professor of Journalism at Dublin City University and the author of biographies of Sean Lemass and Mary Robinson