Mark Twain on truth and fiction

Mark Twain's instructions were quite clear: his autobiography was to remain unpublished until 100 years after his death. You couldn't imagine a writer doing something like that these days. Who could resist a pay cheque in the here and now for deferred immortality in the hereafter? More to the point, could any modern writer be certain their lives would still be interesting to anyone so long after their death?

Hubris never came into Twain's calculations. He was the American writer, the rags-to-riches embodiment of the American dream, and it never seems to have occurred to him that his popularity would fade. Nor has it. He is still the writer before whom everyone from Faulkner to Mailer has knelt. And even though his literary executors might not have followed his instructions to the letter – various chunks of his autobiography have been published over the years – this year's publication of the first of three planned collections of Twain's full autobiographical writings to coincide with the centenary of his death has still been one of the literary events of the year.

Still more remarkable is that Twain's reputational longevity is based on so few books. As John Sutherland, emeritus Lord Northcliffe professor of English at University College London, points out, "Huckleberry Finn has been largely off-limits in American schools and colleges because of Twain's use of the word "nigger", so most readers only know him for his aphorisms and Tom Sawyer. And even that is overrated. Dickens published 12 novels, any one of which can be argued to vindicate his status as Britain's greatest. Where are Twain's dozen? What makes him the 'father' of American fiction?"

Sutherland suggests the answer lies in voice, eye and attitude. Twain was a gifted public speaker; he turned literature into something that was heard as well as seen; and cast himself as an innocent, with a decidedly jaundiced, feisty gaze on the rest of the world. "Take these three elements," he says, "and, as Hemingway argued, you have the essence of a national literature. After Twain, no one could dismiss it as 'English literature written in America.' It was itself."

And it's the voice that shines through his autobiography. "The general reader gets to see the man beyond the aphorisms," says Harriet Smith, editor of the Mark Twain Project, "but for the serious academic there are no new facts about his life revealed. What we get is him speaking to us from beyond the grave; even in the passages that seem quite boring his appeal still resonates for the infelicities – rather than being a flaw – are a window into how he thought and what jogged his memory."

Above all, there is no linear narrative. He first toyed with the idea of writing his autobiography in the 1870s but abandoned the idea because he couldn't find a way of telling the truth about himself. Finally, after the death of his wife, Olivia, in 1904, he came up with two solutions. The first – almost certainly borrowed from the Freudian psychoanalytic model of free association – was to dictate his thoughts to a stenographer; for 15 minutes each day he would start by deliberating on an item of news that had captured his attention and see where it led. The second was to self-impose a 100-year rule, so that by the time any judgment was passed he would be "dead, unaware and indifferent".

Not that any of this necessarily had the desired effect. "If you're relying on memory," says novelist Michael Frayn, "how – even with the best of intentions – can you distinguish between what you remember and what you make up? A biographer can seek corroboration elsewhere; a personal memoir does not have that advantage." Biographer Claire Tomalin takes this further. "Any journal that is intended for publication – even in 100 years' time – is probably in some way compromised. The only person I can think of who got close to an unexpurgated truth is Samuel Pepys, and that's because his diaries were never meant to be read."

Blake Morrison, whose two memoirs of the lives – and as importantly – deaths of both his parents were both bestsellers, concludes that a writer can only tell his or her truth and that you just have to accept it may not be someone else's. "I did make some compromises," he says. "I gave the manuscript of When Did You Last See Your Father?' to my mother to read and made a number of small changes – including concealing the fact she was a Catholic – she requested.

"But I wasn't conscious of deliberately suppressing anything. In fact, the reverse. Sometimes it's easier to say something on the page rather than in person: I certainly got a few odd looks in the office the week after the book was published and everyone had read 'that' passage about me masturbating in the bath."

You certainly won't find anything like that in the Twain autobiography. Indeed, he as good as admitted that in many instances he didn't even try to tell the remorseless truth when he wrote that he could think of 1,500 incidents of which he was ashamed and had not put to paper. "Even the two shameful incidents of which he does write – being unable to prevent his young son from falling in the river [he went on to catch diphtheria and die] and not allowing his wife to visit a friend in Scotland – are hardly the stuff of deep shame," says Smith.

There's an obvious danger here of applying 21st-century values to something that was written in the early years of the 20th century. Yet there is something quintessentially modern about Twain. Not least in the blurring of his public and private personas. Twain's real name was Samuel Clemens: his nom de plume derives from the Mississippi boatmen's cry for "safe passage". Yet despite a fierce attachment to the idea of telling the truth, it never seems to have occurred to him to call the book The Autobiography of Sam Clemens. Much in the way that Bono and Sting never use their real names today. To his readers, to his friends – and, above all, to himself – Mark Twain was every bit as real as Sam Clemens.

Twain understood the value of his image and went to some lengths to protect it. Some of the more fascinating passages in the autobiography are those that have been crossed out. These are, more often than not, the ones about which he was particularly sensitive. And they aren't to do with the personal, such as his feelings of loss over the deaths of his wife and daughter, Susy, or his suspicions about being financially ripped off by his manager, Ralph Ashcroft, and his secretary, Isabel Lyon. They are about the abstract. Such as religion.

"There are some extracts, including one in which he confuses the Virgin birth and the Immaculate Conception, in which he declares his religious scepticism robustly, about which Twain was extremely nervous," says Smith. "He was so worried he would be ostracised and shunned for this by God-fearing Americans that he actually set a publication date of 2406 for those sections."

Imagine. A man so protective and nervous of his own reputation that he sought to keep some of the ideas he thought might alienate his public silent for 500 years. Yet equally a man so sure of his reputation that he had no doubts people would still want to read him 500 years after his death. There, in essence, is Twain's ambivalence between the public and the private, between truth and spin. Needless to say, his executors didn't adhere to the 500-year diktat and the American public continue to adore him regardless. Then Twain being Twain, he'd have hardly expected anything less.