Mark Twain

Samuel Langhorne Clemens was born on 30 November 1835 in Florida, Missouri, and grew up in Hannibal on the Mississippi, which became the model for Tom Sawyer's St Petersburg. He worked as a printer's apprentice, then trained as a steamboat pilot on the river, a job he described as the best he ever had and which ended when the Civil War closed traffic. The pen name comes from the river: mark twain is the call for two fathoms, safe water.

He made his name with humorous sketches and travel writing - The Innocents Abroad in 1869 was a bestseller - and then wrote The Adventures of Tom Sawyer in 1876 and Adventures of Huckleberry Finn in 1884. Hemingway's judgement, that all modern American literature comes from Huckleberry Finn, is the most quoted sentence about it, and the book's use of vernacular speech rather than literary English is why.

What happened to Twain's money?

He invested enormous sums in the Paige typesetting machine, an ingenious and impossibly complex device that was overtaken by the Linotype, and it ruined him. He was not legally obliged to repay his creditors in full after the bankruptcy and did it anyway, undertaking a lecture tour around the world in 1895 and 1896 to earn the money, in his sixties. The later years were dark: his daughter Susy died of meningitis while he was abroad, his wife Olivia died in 1904 and his daughter Jean in 1909, and the writing turned bitter and metaphysical - The Mysterious Stranger, the Letters from the Earth, the unpublished material his estate withheld for decades. He died on 21 April 1910.

Twain is dominant Ne, and the career shape gives it away: printer, riverboat pilot, silver prospector, journalist, travel writer, novelist, lecturer, publisher, inventor and investor. He kept generating, and his best writing has the same quality - a voice that moves by association, doubles back, digresses and arrives at the point from an angle nobody expected.

The auxiliary Ti is why the humour has teeth. His method is to take a piece of received wisdom, examine it seriously, and follow it until it falls apart - which is how the Huckleberry Finn raft sequence works, with a boy reasoning his way through the conventional morality he has been taught about slavery and concluding, in the novel's most famous line, that he will go to hell instead. That is a logical demolition delivered in a child's voice.

Why did the late work turn so dark?

Because tertiary Fe was where the losses landed and there was nothing above it to absorb them. Susy, Olivia and Jean died within fifteen years, and the writing turned from satire against institutions to something much colder about the species itself. The inferior Si is the whole financial catastrophe: he backed a mechanically dazzling machine without any accumulated sense of what production, cost and competition would actually do to it, and then repaid the debts through sheer output, which is the only remedy this stack has.

ENFP is sometimes suggested because of the warmth and the enormous public affection. The difference is the auxiliary. Ne with Fi produces a moralist writing from conviction; Twain's method is analytical demolition - he takes an argument seriously in order to destroy it - and his most powerful moral moments are reached by reasoning rather than asserted.

ENTJ is occasionally proposed because of the publishing house and the business ventures. But the ventures were enthusiasms rather than strategy, and most of them failed. He generated and moved on, and the one thing he executed with real discipline was a lecture tour undertaken to clear debts he had created by not executing anything else.