The two other daughters were to join them until they received a cablegram that the youngest, 22-year-old Susy, was ill. She died of meningitis before her family could return.
"It was a real tragedy," Lovell said. "Life was never the same."
Twain had lost a 19-month-old son to diptheria and Jean would drown in 1909 during an epileptic fit in the bathtub after her sister Clara insisted she return home.
Twain adored his wife Olivia, who was 10 years his junior.
"These two really got each other," Lovell said. "She was very intelligent and well read and up to speed on world events. She was his intellectual equal and edited him."
The passages Twain writes at her death in 1904 are "fresh and raw."
"He writes in real time," she said. "You feel as though you are talking to a man who lost his best friend."
But the autobiography reveals another haunting love, 14-year-old Laura Wright, whom he met decades earlier on a Mississippi pier while working as a steamboat captain. So smitten was he with her that he consulted a fortune teller.
Twain was as mystical as he was pragmatic and worldly.
He convinced his brother Henry to work with him on that steamboat, which exploded in 1858, killing his brother. Twain insisted he had foreseen the tragedy in a dream a month earlier. Twain was also an early member of the Society for Psychical Research.
The autobiography is grounded in America's narrative: from the Southern slavery to the 1849 Gold Rush and expansion of the West to the Civil War and the Guilded Age.
"Whether by design or by accident or by dumb good luck," Lovell said. "This man was at the front in center at every major historical event during his lifetime."