Explorers have long chased after chimeras - the gold of El Dorado, the lost city of Atlantis - but the 300-year quest for the Northwest Passage was not merely the pursuit of a fantasy.
Such a route, connecting the Atlantic and Pacific via a thicket of ice-choked straights, sounds and islands off Canada's northern shores, actually did exist - it was finding a way through it that proved impossible.
From the 16th through the 19th centuries, the ice tempted and defeated a procession of dogged navigators looking for a shorter route to the riches of the East.
That, at least, was the theory. The reality of the Northwest Passage proved altogether more fiendish and intractable.
Journeys into the Northwest Passage were anything but short. Ships were trapped in the ice pack for years at a time, while their crews endured cold, disease, scurvy, starvation - some resorted to cannibalism - and the long ordeal of the Arctic winter. It was the British, looking to outflank their Portuguese and Spanish imperial rivals, who led the way into the ice.
Charting the passage became an idée fixe of the Royal Navy, which made expeditions in the middle decades of the 19th century with the hopes of finally solving the riddle of the Arctic seas.
The ships were lavishly supplied with the innovations of the day, among them tinned meat and steam engines, while some even had primitive heating systems.
The journeys yielded many scientific and cartographic findings - much of the North American Arctic was mapped - even if the passage's commercial promise was never realised. In The Man Who Ate His Boots, Anthony Brandt beautifully evokes the foolhardiness and pathos of these voyages.
Heroes made their name braving ridiculously extreme conditions - winter temperatures could plunge to 50 below and not let up.
Arctic summers, however brief, were no picnic either - mosquitoes and black flies feasted on caribou and men in equal measure.
The "man who ate his boots", Sir John Franklin, really did eat his boots. Trekking across the Canadian tundra in the 1820s on a map-making mission for the Royal Navy, Franklin, low on supplies and desperately hungry, survived on bits of lichen and shoe leather.
Two decades later, Franklin, along with the crew he commanded, suffered a far grimmer fate when he sailed into the pack ice and was never seen again.
The futility of it all gives one pause. The British, it must be said, have a peculiar fascination with icy extremes - there is a line linking Franklin to Robert Falcon Scott and his botched race to the South Pole, and the ill-fated attempts of George Mallory to summit Mount Everest in the 1920s.
For Brandt, the search for the Northwest Passage was a kind of ennobling tragedy: "Men suffered and died in the Arctic in a great cause, to open an entire region of the globe to science and human traffic, however unreal it was at the time to envision sailing through water frozen to a depth of 40 feet," he observes.
"Should they have stayed home and waited for global warming to open a way through the ice? No easy answer suggests itself. To behave nobly and heroically in an obviously hopeless cause is a kind of folly, but it can also constitute a kind of greatness. Despite the wrongheadedness of the enterprise, an air of transcendence arises from their sufferings."
Brandt, editor of the National Geographic Society's Adventure Classics series and a contributor to GQ and other publications, shapes his material with the pungent brio of a magazine writer.
His style can be a little overheated - for a more sober compliment to Brandt, consult Arctic Labyrinth by Glyn Williams, one of the finest scholars of Northwest Passage history - but his accounts of the voyages are models of their kind, flecked with drama and keen insight into character and motive.
Brandt also provides keen insight into the geographical and logistical dilemmas that dogged nearly all the missions. Among other things, the search for the Northwest Passage is a study in error and misapprehension.
The Royal Navy figure in charge of Arctic exploration, John Barrow, the second secretary of the admiralty, had rather eccentric notions about sea ice.
Barrow himself never ventured to the Arctic but was convinced the Northwest Passage was a viable sea route. He firmly believed ice could not form on the open sea and against the testimony of seafarers, whaling captains who sought their prey in frozen waters, Barrow countered: "Ice may occasionally be formed on the surface of such an ocean, it never arrives at any considerable thickness, but is broken up and dispersed by every gust of wind." Barrow was a theorist of the Northwest Passage - it was for others to actually smash their way through the maze of the Canadian archipelago.
Among these figures was William Edward Parry. The very model of a Royal Navy officer, Parry was handsome, intelligent and attentive to his men. He was the first to winter over in the Arctic and his voyage of 1819-1820, which took him deep into the western reaches of the archipelago, is still considered one of the most successful attempts to find the passage.
He fixed a template his successors would emulate. He built an observatory on shore and his officers gathered meteorological data. The crew put on plays and kept busy with regular duties.
Parry believed the passage was there for the taking. Still, the terrain was pitiless. On a subsequent voyage, Parry mused of his icy surroundings that "all is dreary monotonous whiteness - not merely for days and weeks, but for more than half a year together. Whichever way the eye is turned, it meets a picture calculated to impress on the mind an idea of inanimate stillness ... in the very silence there is a deadness with which a human spectator seems out of keeping."
The British, however, would not stay away from the Arctic. As Brandt observes, the admiralty treated the ice with an arrogance that would ultimately prove fatal.
Casualties were a factor on any mission - scurvy was a constant menace - but what befell the crews of the HMS Erebusand HMS Terrorwas horrific.
In 1845, the ships, under the command of Sir John Franklin, set off from London on what would be the climactic mission to Arctic waters.
Franklin was an unlikely leader with none of Parry's dash.
But his previous exploits, when he dodged calamity on his overland trek, had earned him heroic status in Victorian England.
Franklin would not be so lucky on his return to the Arctic. In a sense, the mission was doomed from the start. An impatient Barrow, desperate to prove the viability of the passage, had ordered the ships to sail into the pack ice, which, he believed, would lead the ships to open water.
But flawed and incomplete maps of the archipelago also contributed to problems that overwhelmed the Franklin mission. There was debate about the wisest route but no consensus.
One sceptic darkly warned that Barrow was sending Franklin "to become the nucleus of an iceberg". He was not far off the mark.
The disappearance of the Erebusand Terrorprompted a litany of search expeditions, which themselves got bogged down in the ice.
The search for Franklin was its own epic. The feats of the search parties boggle the mind - men criss-crossing the ice, hauling 1,000 kilogram sledges for hundreds of miles.
As the years passed, grim news filtered back to England about the 129 men of the expedition.
They perished, slowly, from a combination of scurvy, starvation and exposure. In recent years, forensic research has also added lead poisoning to the list.
Brandt does not embellish when he writes: "Their deaths were ugly, a scene out of a Gothic novel or Dante's Inferno. There was no trace of dignity in the record left by their bones, which had been broken open by the last survivors for their marrow."
Allegations of cannibalism, still controversial, dismayed the Victorian public. Charles Dickens weighed in, calling the charges "gigantically improbable". A preponderance of evidence supports the claim but perhaps the definitive statement about these desperate measures is best left to George Back, who accompanied Franklin on his first overland journey: "There is little compassion in the human frame I believe, when it is in a state of privation."
Did the men of the Franklin mission resort to "the last dread alternative"? "Very few of us have ever been hungry enough to know," Brandt writes. Thank goodness for that.
Matthew Price's writing has been published in Bookforum, the Los Angeles Times, The Boston Globe and The Financial Times.