Winnie & Nelson: Portrait of a Marriage, by Jonny Steinberg (Jonathan Ball Publishers)

A politically aware friend of a friend said she was not planning to read  this book. That would lend credence to what seemed to be an invasion of the privacy of the Mandelas and their marriage.

Certainly there is some truth to this. The book includes word-for- word transcriptions of private conversations between Winnie and Nelson Mandela, recorded by the prisons department when Winnie visited her husband on Robben Island, the sort of material biographers rarely have access to.

Should these conversations have been included?

It turns out my friend’s friend is not the only one. Wits associate professor Hlonipha Mokoena interviewed author Jonny Steinberg at the Franschhoek Literary Festival last month and said while reading these sections she felt “a profound sense of shame”, as though she too, like the listening prison warders, was behind that one-way glass, hearing people’s private feelings. It made her feel complicit.

Steinberg conceded the ethics of the situation were difficult, because these intimate conversations between a wife and a husband  were recorded only because he was in prison. He said the transcripts should have rightfully and legally ended up in the national archives, where access would have been restricted.

However they did not, for the simple reason that the last apartheid justice minister, Kobie Coetzee, stole them and took them home.

Steinberg went on: “I’m probably the last person on earth to give a credible ethical defence for using them. I wanted to use them because I was writing this book. The fact they were there, I could use them and I was writing a book on this marriage meant I was not going to not to use them.”

But the question was, he said, could he preserve the speakers’ dignity and write about them with sympathy? This would be for the readers to judge.

It seems to be one of those questions along the lines of: the public is interested, but are the revelations in the public interest? Considering how central the marriage was to Nelson Mandela, the man he became and the negotiated political settlement  that resulted, I’d say they are in the public interest.

Because, as Steinberg points out, as Nelson’s incarceration continued for year after devastating year, the idea of his marriage grew more and more important to him. And the tragedy was that while he  more in love with the beautiful 26-year-old he had left at home when he went to jail, he was becoming increasingly out of touch with the real-life woman, to the point he barely knew her.

And by the time he emerged from prison 27 years later, their politics had drifted a long way apart, with Nelson convinced only a carefully negotiated settlement could end apartheid, while Winnie believed fiercely, like Govan Mbeki, that the solution lay in a bloody, armed conflagration.

Winnie’s interrogation by the security policeman Theunis Swanepoel in 1969 had a profoundly damaging effect on her. “She remembered his raw hatred. And she described absorbing that hatred and making it her own.”

By time Nelson was released, Winnie had become increasingly associated with violence.

I doubt I would have read this book had it been written by anyone other than Jonny Steinberg. He is measured, thoughtful and meticulous. It is also, like his other books such as the brilliant Three-Letter Plague, riveting. It provides all sorts of insights that might not have occurred to the reader, certainly not this one.

It is also a relook at South Africa’s recent history seen through the prism of this marriage, and I found there were many things I’d forgotten, or had never known.

One minor one was the fact that when Nelson was released from jail in 1990 Winnie was having an affair with the-then little-known lawyer Dali Mpofu, and when Nelson made his famous speech from Cape Town’s City Hall, Mpofu was up there on the balcony with them both.

Steinberg makes it clear that before he went to prison, Nelson was a terrible husband and father, but the idea of his wife and family helped keep him sane and able to cope with incarceration.

This marriage was, in a sense, a farce between two people who had increasingly little in common. However Nelson, at the beginning of his freedom, was prepared to do what he could to preserve it. To this end, says Steinberg, he abused his power severely, notably when Winnie went on trial for the kidnapping of Stompie Sepei.

Eventually though, a humiliated, bitterly angry Nelson left Winnie. Steinberg told Mokoena it was hard to separate the political from the personal in their marriage, but in the end he believed Nelson’s motives were “deeply personal”.

The Mandelas were a magnificent couple, beautiful, flawed and subject to unimaginable privations. We should hesitate to judge.

Winnie & Nelson is in no way prurient nor gossipy, but tells us a lot about our country now. Their marriage and its consequences affect us all to this day.

Read it.

• Winnie & Nelson is one of Exclusive Books’s top reads for June.