Gary Scharnhorst at The Paris Review:
Over a century and a half ago, a columnist for the San Francisco Daily Dramatic Chronicle predicted that Samuel Langhorne Clemens, aka Mark Twain, was “bound to have a biographer one of these days—may it be a hundred years hence!” Albert Bigelow Paine’s official biography of the author was published less than fifty years later. It is an indispensable source for the legend of Saint Mark. Paine portrayed his subject as “the zealous champion of justice and liberty” who was “never less than fearless and sincere. Invariably he was for the oppressed. He had a natural instinct for the right, but, right or wrong, he was for the underdog.” As recently as 2002, Robert E. Weir echoed the dubious claim: Sam “was an indefatigable foe of anything that stood in the way of human progress and individual potential,” as if to suggest that the world would be a better place if only everyone emulated him. Sam Clemens’s most honest comments about his life, or so he asserted, appear in his autobiography, most of which appeared posthumously. “A book that is not to be published for a century gives the writer a freedom which he could secure in no other way,” he explained in 1899. “In these conditions you can draw a man without prejudice exactly as you knew him and yet have no fear of hurting his feelings or those of his sons or grandsons.” “I speak from the grave rather than with my living tongue, for a good reason,” he declared. “I can speak thence freely.”
more here.