Here is a book which, literally, takes all of us in this city out of the darkness and into the light. And at long last too.

Start with Mark Twain’s very house at 472 Delaware Ave. You could still see it when I was a boy. It was large but no “mansion” as it’s sometimes described – not, in any case, like so many of the other magnificent houses on Delaware two blocks away. Its frontage on that magnificent street was hardly imposing. The only thing that identified it as something very special indeed was the plaque that told us it was the house Mark Twain lived in during the time he was the editor of the Buffalo Express from 1869 to 1871.

You could still walk up to its door and peer through its windows. A couple of us did as young boys, a few years before they tore it down. It was indeed as dark and unprepossessing from the outside as any Delaware Avenue landmark could possibly be, even though in retrospect it is now second only to the Wilcox Mansion in historical importance. That’s not how it looked. It seemed back then a house only Charles Addams could love.

We think about these things so very differently now. Back then, there were those who might well have privately called it an “eyesore” or “white elephant.” No huge protest from preservationists accompanied its razing or the construction of an upscale, flame-illuminated restaurant called The Cloister in its place.

The physical darkness of that house has, for very good reasons, symbolized historical accounts of the brief residence of the most famous and important figure ever to reside, however briefly, in our fair city.

And now something else – genuinely new revisionism in what has to be seen as the great book some of us have quite literally waited all our lives for: the definitive book about Mark Twain’s Buffalo residence.

It deserves, in fact, to be accorded a huge place in the Buffalo bookshelf when it is published in mid-March along with Lauren Belfer’s novel “City of Light,” Tim Russert’s “Big Russ and Me,” Verlyn Klinkenborg’s “The Last Fine Time,” Mark Goldman’s two books and Reyner Banham’s utterly irreplaceable “Buffalo Architecture: A Guide.”

It’s important to note here that in 1999, editors Joseph B. McCullough and Janice McIntire-Strasburg published a Twain collection that can now be seen as the crucial companion book to Reigstad’s: “Mark Twain at the Buffalo Express” (Northern Illinois University Press.)

But don’t let the awkward and amateurish title of “Scribblin’ for a Livin’ ” fool you. Inside the book is the exhaustive, extraordinary history of Mark Twain in Buffalo that so many have wanted for so long. To call it definitive at this particular moment may well be understatement. As University at Buffalo professor Neil Schmitz quite rightly observes in the book forward, “this is it. There isn’t any more to be said about Mark Twain in Buffalo. If you want to think about the subject or write on its issues, this is the book that is open before you.”

And it is, as I said, far from beholden to past histories, for all their renown and prizes. Reigstad has done his own exhaustive research, including with ancestors of Twain’s Buffalo friends.

Reigstad, for one thing, insists that Twain’s Buffalo residence, as his subtitle says, was “pivotal” not of negligible import as is so often claimed. It is here in Buffalo “where he decided to stop writing for newspapers and start writing books.”

Nor, Reigstad maintains, was Twain put off by Buffalo weather, that cliched nemesis so easy to toss into the air the minute Buffalo is mentioned. “If anything,” he writes, “Twain seemed favorably disposed to Buffalo’s climate, even embracing its notorious winters.”

“This book is not meant as a defense of Buffalo,” writes Reigstad. “I am well aware of Buffalo’s collective but undeserved inferiority complex and have found it curious that in a sense it carries over to Twain scholarship.”

Even so, Reigstad is no fool. Far from it. So much death and illness bedeviled Twain and his wife Olivia while they lived here that only a fool could ignore the misery. Twain’s own words, at one of his darkest moments, made his feelings clear. “Two weeks before moving” to Elmira, says Reigstad. “he wrote [in a letter] that he had grown ‘at last to loathe Buffalo.’ ”

It was in Buffalo that Twain and his new wife Olivia were living when her wealthy father Jervis Langdon – who had given the young couple that plush Delaware Avenue home – died of cancer. It was here that Olivia nursed a friend who wound up dying of typhoid.

Reigstad reports that during Olivia’s difficult pregnancy, the nearby Cornell leadworks “could not hide the tall end-to-end chimneys that belched coal smoke and other toxic chemical elements – such as arsenic – necessary to manufacture their flourishing line of lead products. … In nineteenth century industrial America … ‘not uncommonly houses stood right up against gasworks, rollings mills, and paint factories, exposed to round-the-clock noise and poisonous discharges’  ” in the words of James Howard Kunstler, quoted by Reigstad.

Who knows what effect it had on her?

Baby Langdon Clemens was born a month premature weighing only four and a half pounds. He was not expected to survive long. “Twain described his unpleasant final week of life in Buffalo as a ‘state of absolute frenzy’ as being for weeks ‘buried under beetling Alps of trouble’ and of feeling ‘half-crazy.’ He wrote [in a letter] that he was so stressed that ‘if that baby goes on crying three more hours this way, I will butt my frantic brains out.’ ”

Eighteen months after Langdon was born, when the family had moved to Elmira, he was dead of diphtheria.

And yet Reigstad’s exhaustively detailed look at Twain’s life in Buffalo makes it clear how many of his associations here continued for the rest of his life – in particular his lifelong friendship with David Gray, editor of the Buffalo Daily Courier, the paper that later merged with the Express.

Reigstad is utterly uninfected by any temptation to gloss over Twain’s human deficiencies.

His is a Twain who, as a newspaper editor, insisted on a concise writing style he had no intention of employing himself. Reigstad’s Twain is an often difficult and cold man who, as with almost all those publicly cherished for humor, was always surprising those he encountered in the world with his lack of it.

At the same time, he often wrote wonderfully for the Express during the period following the publication of “Innocents Abroad” and coinciding with his planning and writing “Roughing It.”

In his opening “Salutatory” at the Express, he promised his readers “I am not going to introduce any startling reforms, or in any way attempt to make trouble. I am simply going to do my plain, unpretending duty when I cannot get out of it.” He also pledged “I shall always confine myself strictly to the truth, except when it is attended with inconvenience.”

He vowed not to “meddle with politics because we have a political editor who is already excellent, and only needs a term in the penitentiary in order to be perfect.”

Published for the first time in this terrific book are some of Twain’s least prepossessing writings for The Express, including “People and Things” columns few, if any, would ever think of as from one of America’s greatest – indeed one of its cardinal – literary titans.

The first one included is dated Aug. 17, 1869. We learn that “Mr. Geo. Peabody is no better.” And “they have California honey and Chinese shoes for sale in Chicago.” and “258 Marriages and 282 births last week in New York.” And “Miss Nellie Fenton, daughter of the Senator, is shortly to marry J.N. Hegeman of New York, druggist.”

Reigstad is himself a well-traveled ex-journalist as well as a retired English professor at Buffalo State College. He has written for Bills Insider, Business First and Western New York Heritage, among other outlets. He “worked at the Courier Express off and on as a features writer and copy editor right up to the last night it existed, Sept. 19, 1982.”

I have never met Mr. Reigstad. But simply on acquaintance with his book, I can think of no one more fitting to have written a book that from now on ought to be in any decent Buffalo library.

Scribblin’ for a Livin’: Mark Twain’s Pivotal Period in Buffalo

By Thomas J. Reigstad, foreword by Neil Schmitz

Prometheus Books; 301 pages, $19 paperback, for sale March 19

Jeff Simon is The News’ arts and books editor.