Sam intended to give us an unblushing autobiography on the order of Casanova’s or Rousseau’s “Confessions” or Samuel Pepys’s diary, which Sam heartily admired, with its matter-of-fact inventories of parties attended and meals enjoyed and the skirts of chambermaids raised, but he knew that frankness comes with a price — “None of us likes to be hated, none of us likes to be shunned,” he said. “The man has yet to be born who could write the truth about himself” — and when he describes his brother Orion as having “an intense lust for approval,” he is surely describing himself: “He was so eager to be approved, so girlishly anxious to be approved by anybody and every­body, without discrimination, that he was commonly ready to forsake his . . . convictions at a moment’s notice. . . . He never acquired a conviction that could survive a disapproving remark from a cat.” The younger brother sees the older with a clear satirical eye, and what he sees is himself. Orion was foolish about money and so was Sam, a spendthrift to the end. Their father, Judge Clemens, before Sam was born, bought 75,000 acres of land in Tennessee. It contained coal, copper, iron, timber, oil, and produced wild grapes — “There’s millions in it!” said a cousin, James Lampton — and “it influenced our life,” Sam writes, it “cheered us up, and said ‘Do not be afraid — trust in me — wait.’ It kept us hoping and hoping, during 40 years, and forsook us at last. It put our energies to sleep and made visionaries of us — dreamers, and indolent. We were always going to be rich next year.” When their father died, “we began to manage it ourselves, . . . managed it all away except 10,000 acres,” which Orion traded for a house and a lot worth $250. The only one to turn a profit was Mark Twain, who turned Mr. Lampton (“the happy light in his eye, the abounding hope in his heart, the persuasive tongue, the miracle-­breeding imagination”) into Colonel Sel­lers in “The Gilded Age.”

It is the sad fate of an icon to be mummified alive, pickled by his own reputation, and midway through this dreary meander of a memoir, Sam throws up his hands in despair. “What a wee little part of a person’s life are his acts and his words! His real life is led in his head, and is known to none but himself. . . . His acts and his words are merely the visible thin crust of his world . . . and they are so trifling a part of his bulk! a mere skin enveloping it. The mass of him is hidden — it and its volcanic fires that toss and boil, and never rest, night nor day. These are his life, and they are not written, and cannot be written. . . . Biographies are but the clothes and buttons of the man — the biography of the man himself cannot be written.” There is very little real feeling here and no volcanic fires until you come upon the account of the death of his daughter Susy, 24, in Hartford, of meningitis, on Aug. 18, 1896. It is agony to read. Susy took ill and was taken to the house in Hartford, the home of her childhood, where she once wrote: “We are a very happy family. We consist of Papa, Mamma, Jean, Clara and me.” Her mother and Clara set sail from England to be with her. Her sister Jean and an aunt and uncle and some servants and the minister Joseph Twichell were at the bedside. Meningitis set in on the 15th. She ate her last supper that evening. The next morning, a high fever and delirium. She mistook a gown hanging in the closet for her mother and clutched it, kissed it and wept. She went blind. She stroked the face of Katy Leary, the housemaid, and said her last word, “Mamma.”

The father writes, “How gracious it was that in that forlorn hour of wreck and ruin, with the night of death closing around her, she should have been granted that beautiful illusion . . . and the latest emotion she should know in life the joy and peace of that dear imagined presence.” Susy was unconscious for two days and died on a Tuesday at 7 p.m. — “she that had been our wonder and our worship.” Sam was in England when he got a cablegram on Aug. 18 that said, “Susy was peacefully released today.” (“It is one of the mysteries of our nature that a man, all unprepared, can receive a thunderstroke like that and live. . . . The intellect is stunned by the shock and but gropingly gathers the meaning of the words. . . . It will be years” before he truly knows “the magnitude of his disaster.”)

Of all the cruel deaths in the book — the death of Sam’s father just when prosperity seemed to be in his grasp; the death of his younger brother, Henry, when boilers burst on a steamboat in 1858 (Henry, who had taken a job on the boat at Sam’s urging); the death of the infant son Langdon Clemens, for which Sam felt responsible — the death of the beloved daughter far beyond her father’s love and care is a disaster from which there is no recovery. Boyishness cannot prevail, nor irreverence. The story can’t be written. The man buttons up his clothes and resigns himself to the inexpressible.