In Conversation with Nelson Mandela, the reluctant South African president

Nelson Mandela never wanted to become South African president and would have preferred a younger person to become the country's first black ruler, according to a new book.

Mandela states in the book Conversations with Myself, due to be launched today, that he only accepted after senior leaders of the African National Congress put pressure on him.

"My installation as the first democratically elected president of the Republic of South Africa was imposed on me much against my own advice," Mandela said.

The book, compiled by the Nelson Mandela Foundation from personal letters, interviews and an unpublished sequel to his autobiography Long Walk To Freedom, contains a foreword by US President Barack Obama.

Mandela, 92, said he would have preferred to serve the new South African state without holding any position in the ANC or government. After being pressured by one of the ANC's leaders, he changed his mind, but made clear he would serve only one five-year term.

Mandela's release on 11 February, 1990, after 27 years in apartheid-era jails, set in motion the country's transformation to democracy, which culminated in historic all-race elections in 1994 and his inauguration as the country's first black leader.

In the book, an important theme is his concern about the effects of his imprisonment on his family. Mandela shows his anguish and frustration in one letter to his former wife Winnie Madikizela-Mandela, who was banished to a remote town and harassed by police.

"I feel I have been soaked in gall, every part of me, so bitter am I to be completely powerless to help you in the ordeals you are going through."

He also writes about not being able to attend the funerals of his mother and of his son, who died in a car accident in 1969. "My heart bled when I realised I could not be at the graveside - the one moment in life a parent would never like to miss."

Conversations is best read as a companion to Long Walk To Freedom, which was in part calculated by Mandela and other members of his ANC party to stir support for them as new leaders.

Certainly, the possibility of violence within Mandela's first marriage, to Evelyn Mase, who died in 2004, had no place in the official autobiography. But it has been raised elsewhere, including Young Mandela, an unauthorised biography.

In Conversations, Mandela puts his version on record. In a transcript of a conversation with Ahmed Kathrada, a friend who was helping him polish Long Walk, Mandela denies he once tried to choke his first wife.Instead, he said, she threatened to burn him with a red hot poker.

"So I caught hold of her and twisted her arm, enough for me to take this thing out," Mandela says.

"The poker away," Kathrada responds.

Mandela: "That's all."

The book also has some humour. In 1987, while studying for a further law degree in prison at the age of 69, Mandela applied for exemption to study Latin saying he had already passed Latin in 1944 and "I have forgotten practically everything about it".

The book concludes with Mandela saying in the unpublished sequel to his autobiography that while he was in prison he worried about a false image he was projecting from jail as being regarded a saint. "I never was one, even on the basis of an earthly definition of a saint as a sinner who keeps trying."