"It will be unparalleled in the history of literature," predicted the Times in 1899 of Mark Twain's autobiography. "A bequest to posterity." Now, 100 years after the author died, his complete memoirs will be made public for the first time.

Twain had specified that his autobiography remain unpublished for a century after his death, to ensure that he felt free to speak his "whole frank mind", knowing that when his "Final (and Right) Plan" for relating the story of his life was eventually published, he would be "dead, and unaware, and indifferent". The author passed away on 21 April 1910, and this November, the University of California Press will publish the first volume in the "complete and authoritative edition" of his autobiography, promising that the book would present Twain's "authentic and unsuppressed voice, brimming with humour, ideas, and opinions, and speaking clearly from the grave as he intended".

"When people ask me, 'Did Mark Twain really mean it to take 100 years for this to come out?', I say, 'He was certainly a man who knew how to make people want to buy a book'," editor Dr Robert Hirst told the Independent yesterday. "There are so many biographies of Twain, and many of them have used bits and pieces of the autobiography. But biographers pick and choose what bits to quote. By publishing Twain's book in full, we hope that people will be able to come to their own complete conclusions about what sort of a man he was."

Although parts of the autobiography have appeared in previous biographies of the author, Hirst said that over half of it had never been published before. Running to half a million words, the trilogy of books will cover Twain's relationship with his secretary Isabel van Kleek Lyon, his religious doubts and his criticisms of Theodore Roosevelt, according to the Independent.