Nelson Mandela agonised over the suffering caused to his family by his struggle against white rule in South Africa, in an intimate portrait of the man painted by personal letters and diaries.
Correspondence, personal notes and hours of recordings will be published Tuesday in "Conversations with Myself", which was compiled by the Nelson Mandela Foundation and includes a foreword from US President Barack Obama.
Much of the book is based on an unpublished autobiography that would have been a sequel to his world-famous 1995 "Long Walk to Freedom", including his musings on life as South Africa's first black president.
"I have often wondered whether a person is justified in neglecting his own family to fight for opportunities for others," Mandela said in the book.
"Even when at times I am plagued with an uneasy conscience I have to acknowledge that my whole-hearted commitment to the liberation of our people gives meaning to life and yields for me a sense of national pride and real joy."
Letters from the young Mandela show a side of the Nobel Peace Prize winner now often obscured by the grandfatherly image of the reconciler, now 92, who won South Africa's first all-race elections in 1994.
As a young activist, he pushed the African National Congress to form an armed wing after years of devotion to non-violence as a guiding principle.
"The actual situation on the ground may justify the use of violence which even good men and women may find it difficult to avoid," he said.
"But even in such cases the use of force would be an exceptional measure whose primary aim is to create the necessary environment for peaceful solutions."
In diaries of his 1962 journey across Africa to round up support for the armed movement, he recounts learning to fire a gun in Ethiopia and studying Algeria's military tactics against the French. He was arrested shortly after his return to South Africa.
The book shies away from the most personal details of his life. It barely talks about his first wife Evelyn, although it does recount one violent argument where she tried to burn him with a hot poker.
"So she had put this thing in the coal and it was red hot and as we were arguing she then pulled this thing out, you know, in order to, what-you-call, burn my face. So I caught hold of her and twisted her arm, enough for me to take this thing out," he said.
But his many letters to Winnie Madikizela-Mandela during his second marriage which lasted through his imprisonment, and to his children showed the strains on his family.
"I feel I have been soaked in gall, every part of me, my flesh, bloodstream, bone and soul, so bitter am I to be completely powerless to help you in the rough and fierce ordeals you are going through," he wrote his wife in 1970.
He also remembers feeling gutted when prison authorities refused to allow him to attend the funeral of Thembi, the elder of two sons from his first marriage, who died in a car crash at the age of 24 in 1969.
"When I was first advised of my son's death I was shaken from top to bottom," he said, adding that he had experienced similar heartache when he lost a nine-month-old baby girl several years earlier.
Some of the entries are more mundane, with calendars chronicling his weight and blood pressure, and the arrival of milk and new razors - luxuries in his prison life.
His notes become less detailed after his release in 1990, as he led negotiations with the white apartheid government and then took office.
But he records his own failures, as when the ANC shot down his idea to lower the voting age from 18 to 14.
He also scribbled notes ahead of meetings with world leaders, and in an unexpected show of personality, jotted down the address of his current wife Graca Machel - on a notepad emblazoned with his name and a cartoon of Garfield the cat.
The book ends with a passage from his draft for a new autobiography, asking the world not to beatify him.
"One issue that deeply worried me in prison was the false image I unwittingly projected to the outside world; of being regarded as a saint," he wrote.
"I never was one, even on the basis of the earthly definition of a saint as a sinner who keeps trying."