Howells replied skeptically, “Even you won’t tell the black heart’s-truth. The man who could do it would be famed to the last day.”

Howells was correct. In the end, Sam failed to tell the whole truth and nothing but the truth about his life in his memoirs. From the beginning, he was reticent to discuss sex, for example. “There were the Rousseau confessions,” he acknowledged, “but I am going to leave that kind alone.” He eventually conceded to Howells that “as to veracity,” the entire autobiography “was a failure; he had begun to lie, and that if no man ever yet told the truth about himself it was because no man ever could.” Sam elsewhere declared that “no man dares tell the truth until after he is dead.” His autobiography is so rife with inaccuracies, embellishments, exaggerations, and utter untruths that a cottage industry of naysayers has developed to debunk it. Many parts contain not so much a remembrance of things past but a remembrance of things that did not happen. As Louis J. Budd remarks, scholars who try “to separate truth from yarn-spinning in his autobiographical dictation” have discovered it is “a mountain of funny putty.” Sam Clemens’s biographers must consult the autobiography with caution in reconstructing the events of his life. He never allowed the facts to interfere with a good story, such as the discovery of a blind lead in Roughing It (1872) or his complicity in the death of a stranger in “The Private History of a Campaign that Failed” (1885). Even the apologetic Paine admitted that Sam’s autobiographical dictations bear “only an atmospheric relation to history.” Bernard DeVoto agreed that though he was one “of the most autobiographical of writers,” he was “least autobiographical” when he tried to chronicle his life. Howard Baetzhold describes Sam’s memory as “faulty” and “convenient,” and Hamlin Hill calls it “immensely selective.” James M. Cox refers tactfully to “the magnifying lens of his imagination.”

The first task of Sam Clemens’s biographers, in short, should be to sort facts from factoids or truth from truthiness, a process akin to stripping lacquer from a painting to reveal the original pigments or removing carpet to expose the grain in a hardwood floor. As Sam famously joked, when he was young, “I could remember anything, whether it happened or not,” but as he grew older his memories began to fade, “and soon I shall be so I cannot remember any but the latter.” To arrive at some reliable account of various events, such as Sam’s first lecture engagement in San Francisco in early October 1866 or his putative visit to the czar’s dacha in Yalta in 1867, I have had to triangulate or quadrangulate sources. He seems to have been a yarn spinner from an early age. As his mother once allowed, “he is the wellspring of truth, but you can’t bring up the whole well with one bucket … I discount him 30 per cent for embroidery, and what is left is perfect and priceless truth.”