Above one of the many grand marble staircases within the east wing of Burlington House, the great Palladian mansion on the north side of London’s Piccadilly, hangs a pair of huge sky blue velvet curtains, twisted and tasseled silk ropes beside them. Although many may wonder in passing, rarely does any one of the scores of people who climb and descend the stairs inquire as to what lies behind the drapes. A blocked-off window, perhaps? A painting too grotesque to show? A rare Continental tapestry, faded by the sunlight?

Once in a while someone curious and bold will demand a look, whereupon a functionary will emerge from behind a door marked Private, and with practiced hand win tug gently on the silk ropes. The curtains will slowly part, revealing an enormous and magnificent map of England and Wales, engraved and colored-in sea blue, green, bright yellow, orange, umber-in a beguiling and unfamiliar mixture of lines, patches, and stippled shapes.

“The German Ocean,” it says to the east of the English coast, instead of today’s “North Sea.” There is, in an inset, a small cross-section of what is said to be the underside of the country from Wales to the river Thames. Otherwise all is readily familiar, comfortingly recognizable. The document is exquisitely, beautiful — a beauty set off by its great size, more than eight feet by six-and by the fact that it towers-looms, indeed-above those who stand on the staircase to see it. The care and attention to its detail is clear: This is the work of a craftsman, lovingly done, the culmination of years of study, months of careful labor.

At the top right is its description, engraved in copperplate flourishes: “A Delineation of The Strata of England and Wales with part of Scotland; exhibiting the Collieries and Mines; the Marshes and Fen Lands originally Overflowed by the Sea; and the Varieties of Soil according to the Variations in the Sub Strata; illustrated by the Most Descriptive Names.” There is a signature: “By W. Smith.” There is a date: “Aug 1, 1815.”

This, the official will explain, is the first true geological map of anywhere in the world. It is a map that heralded the beginnings of a whole new science. It is a document that laid the groundwork for the making of great fortunes-in oil, in iron, in coal, and in other countries in diamonds, tin, platinum, and silver — that were won by explorers who used such maps. It is a map that laid the foundations of a field of study that culminated in the work of Charles Darwin. It is a map whose making signified the beginnings of an era not yet over, that has been marked ever since by the excitement and astonishment of scientific discoveries that allowed human beings to start at last to stagger out from the fogs of religious dogma, and to come to understand something certain about their own origins-and those of the planet they inhabit. It is a map that had an importance, symbolic and real, for the development of one of the great fundamental fields of study — geology — which, arguably like physics and mathematics, is a field of learning and endeavor that underpins all knowledge, all understanding.

The map is in many ways a classic representation of the ambitions of its day. It was, like so many other grand projects that survive as testament to their times-the Oxford English Dictionary, the Grand Triangulation of India, the Manhattan Project, the Concorde, the Human Genome — a project of almost unimaginably vast scope that required great vision, energy, patience, and commitment to complete.

But a signal difference sets the map apart. Each of the other projects, grand in scale, formidable in execution, and unassailable in historical importance, required the labor of thousands. The OED needed entire armies of volunteers. To build the Concorde demanded the participation of two entire governments. More men died during the Indian triangulation than in scores of modest wars. The offices at Los Alamos may have housed behind their chain-link fences shadowy figures who would turn out to be Nobel laureates or spies, but they were all hemmed in by immense battalions of physicists. And to attend to all’ their various needs-be they bomb makers, plane builders, lexicographers, codifiers of chemistry, or measurers of the land were legions upon legions of minions, runners, amanuenses, and drones.

The incomparably beautiful geological map of 1815, however, required none of these. As vital as it turned out to be for the future of humankind, it stands apart-because it was conceived, imagined, begun, undertaken, and continued and completed against all odds by just one man. All the Herculean labors involved in the mapping of the imagined underside of an entire country were accomplished not by an army or a legion or a committee or a team, but by the single individual who finally put his signature to the completed document — William. Smith, then forty-six years old, the orphaned son of the village blacksmith from the unsung hamlet of Churchill, in Oxfordshire.

And yet William Smith, who created this great map in solitary endeavor, and from whose work all manner of benefits — commercial, intellectual, and nationalistic-then flowed, was truly at first a prophet without honor. Smith had little enough going for him: He was of simple yeoman stock, more or less self-taught, stubborn and visionary, highly motivated, and single-minded. Although he had to suffer the most horrendous frustrations during the long making of the map, he never once gave up or even thought of doing so. And yet very soon after the map was made, he became ruined, completely. .

He was forced to leave London, where he had drawn and finished the map and which he considered home. All that he owned was confiscated. He was compelled to live as a homeless man for years, utterly without recognition. His life was wretched: His wife went mad-nymphomania being but one of her recorded symptoms-he fell ill, he had few friends, and his work seemed to him to have been without point, without merit.

Ironically and cruelly, part of the reason for his humiliation lies behind another set of faded velvet curtains that hang nearby, on another of Burlington House’s many elaborate staircases. There, it turns out, is quite another map, made and published shortly after William Smith’s. It was in all essentials a copy, made by rivals, and it was made-if not expressly then at least in part with the intention of ruining the reputation of this great and unsung pioneer from Oxfordshire: a man who was not gently born, and who was therefore compelled, like so many others in those times, to bear the ungenerous consequences of his class.

But in the very long run William Smith was fortunate. A long while after the map had been published, a kindly and liberal minded nobleman for whom Smith had been performing tasks on his estate in a small village in Yorkshire, recognized him knew, somehow, that this was the man who had created the extraordinary and beautiful map about which, it was said, all learned England and all the world of science outside was talking.

This aristocratic figure let people-influential and connected people-know about the man he had discovered. He reported that he was hidden, incognito, in the depths of the English countryside. He supposedly had no expectation that anyone would now ever remember, or would ever recognize, the solitary masterpiece that he once had made. He imagined he was doomed to suffer an undeserved oblivion.

But on this occasion his pessimism was misplaced: The messages that had been sent did get through — with the consequence that, eventually, William Smith was persuaded to return to London, to receive at last the honors and rewards that were due him, and to be acknowledged as the founding father of the whole new science of English geology, a science that remains at the core of intellectual endeavor to this day.

It is now exactly two hundred years since William Smith began work on the map that changed the world. What follows, drawn from his diaries and letters, is a portrait of both a long forgotten man and the world in which he lived and worked, as well as the story of his great map, which has remained hidden behind the blue velvet curtains of a great house in London far too long.

From THE MAP THAT CHANGED THE WORLD. Copyright © 2001 by Simon Winchester. All rights reserved. HarperCollins Publishers.