Mark Twain's unpromulgated autobiography(?)

According to this link: http://entertainment.timesonline.co...tainment/books/non-fiction/article7078733.ece , Mark Twain, in his last years, wrote an autobiography in which he exposes the woman he hired as his secretary, who was trying to use blackmail to get much of his estate away from his daughter. He had requested the dossier not be published for 100 years after his death, which is April 21 of this year.

From the article, perhaps the work is negligible, as he seems to be writing from a vantage of revenge, whether the secretary deserved such or not. Regardless, not Twain nor secretary nor daughter appear to have been virtuous during those years.

Do you think it's legitimate? worth reading? too unfairly one-sided? ... or maybe a fake?