A sequel to Nelson Mandela's autobiography, Long Walk to Freedom, will be published next year. Based on material from the Nelson Mandela Foundation's archives, the new, currently untitled, book will document Mandela's time as president of South Africa and will draw from what its publishers, Pan Macmillan, describe as "a substantial but incomplete personally written draft".His widow, Graça Machel, said: "Madiba started working on a manuscript provisionally titled The Presidential Years in 1998. He wanted to put on record his own reflections of those important years in his life."The book he had in mind was to be a natural progression from his autobiography Long Walk to Freedom. Circumstances did not allow him to complete the project. I am very pleased that a team comprising former senior advisers of his have accepted responsibility for completing this unfinished task on his behalf."Pan Macmillan's editorial director, Georgina Morley, said: "The sequel to Long Walk to Freedom will not only tell Mr Mandela's story from his release to his retirement from government, but will also be a rallying cry that will remind readers everywhere what he stood for... "..