In the late 19th century, a letter addressed to “Mark Twain, God Knows Where” was delivered to him. That was celebrity before there existed the supposedly indispensable mechanisms of celebrity — broadcasting and other nation-saturating mass media.

Twain, writes Ron Chernow in his just-published 1,033-page biography, erased the paradigm of the author as a contemplative, cloistered being. Twain “thrust himself into the hurly-burly of American culture, capturing the wild, uproarious energy throbbing in the heartland.” He “fairly invented our celebrity culture, seemingly anticipating today’s world of social analysts and influencers.” Samuel Langhorne Clemens was initially, and ever after as Mark Twain, a writer. But after the huge success of the first of his many books and pamphlets, “The Innocents Abroad” (1869), it was as a platform performer, with his deadpan, hands-in-trouser-pockets drollery, that he achieved acclaim in a country smitten by verbal virtuosity and the humor of rhetorical and other extravagances. He went west when he was young, and Nevada, gripped by the silver euphoria of the Comstock Lode, was wild. To Twain, everything could be wild: “I bit into a peach & the juice squirted across the street and drowned a dog.” P.T. Barnum was Twain’s contemporary.The sort of intellectuals who can tickle a metaphysic from a turnip have discovered in Tom Sawyer and Huckleberry Finn, and in Americans’ embrace of both, a national fondness for rascality or ambivalence about modernity or coded dislike of human nature. Actually, Twain’s writings are about as coded as the Hawaiian volcano whose molten lava Twain observed — and emulated. Chernow says Twain, in perpetual eruption, “couldn’t tolerate more than three or four hours of sleep per night.”

For two weeks early in the Civil War, Twain, much less inflamed than Missouri was about the issues, was a second lieutenant in a Southern-sympathizing militia. He said he was “incapacitated by fatigue” from persistent retreating. Does that self-mockery remind you of someone? In an 1848 congressional debate, a certain representative from Springfield, Illinois, 90 miles due east of Twain’s Hannibal, Missouri, said of his service in the Black Hawk War, “Mr. Speaker, did you know I am a military hero? … I had a good many bloody struggles with the mosquitoes.” Today, such self-deflation is not in fashion in high places.

With previous biographies, Chernow launched Alexander Hamilton toward Broadway stardom and rescued Ulysses S. Grant’s presidential reputation from unjust disdain. His exhaustive but never exhausting Twain biography arrives as the nation is waist deep in condescending populism, by which a political leader courts the common people by exemplifying uncommon coarseness. Twain did something different by recognizing the democracy of dignity.

He was called the “Edison of our literature” when Thomas Edison, the prolific inventor, was a folk hero and Twain was his friend. Twain’s invention was the-vernacular-as-literature, the plainspoken language of ordinary people. With his masterpiece, about 14-year-old Huck, Chernow says Twain “gave voice to the buried portion of the population. … He would revolutionize the American novel by scrapping the omniscient, third-person narrator and allowing the unlettered Huck to tell the tale in his own voice, showing how expressive colloquial language could be. … Twain seems to be eavesdropping on Huck’s thoughts, not inventing them … we hear Huck talking in the idiom of the heartland, in a voice so pure and nature that it grows artful.” In Twain’s day, apologists for the Confederacy argued that slaves had been happy until incited by Northern agitators. Jim, Huck’s companion on the raft, shredded this myth without mentioning it.

When Walt Whitman, Twain’s contemporary, praised baseball for having “the snap, go, fling, of the American atmosphere,” he captured 19th-century America’s crackling energy and appetite for excess. It set the tone of Twain’s platform wit. Whitman might have been singing of Twain, too, when, in “Song of Myself” he compared himself to a hawk:

“I too am not a bit tamed, I too am / untranslatable, / I sound my barbaric yawp over the / roofs of the world.” Another truculent man of American letters, Ezra Pound, wrote, “Literature is news that STAYS news.” Twain’s acidic commentaries on race, democracy, religion, imperialism, Congress and other problems remain relevant. What Robert Frost suggested for his own epitaph — “I had a lover’s quarrel with the world” — could have been Twain’s.

Instead, as Chernow notes, “the most quotable man in American history” was buried beneath a stone bearing none of his words. Later, a daughter added a granite shaft 12 feet high — the two fathoms that Mississippi riverboat hands would signal to pilots as a safe depth by crying “mark twain!”

George Will is a Washington Post columnist.