At a Chelsea-to-Richmond boating party held sometime in the early 1950s, the Duchess of Devonshire, then a beautiful young woman of 30, met a dashing man, some five years her senior, who was dressed as a Roman gladiator and armed with a net and trident. It was a look she thought suited him.

The fancy-dress gladiator was Patrick Leigh Fermor, a former officer in Britain’s Special Operations Executive (SOE), a covert unit that aided resistance movements throughout occupied Europe, and an up-and-coming writer best known at the time for kidnapping a German general during the war. He had crossed paths with the duchess before and remembered her clearly from a regimental ball in 1940, when she was still Deborah Mitford—the youngest of the soon-to-be-famous Mitford sisters. She was then engaged to Andrew Cavendish, a tall naval officer and younger son of the Tenth Duke of Devonshire who had no expectation of inheriting his father’s title until the war took his older brother’s life four years later. Leigh Fermor had watched the couple dance their way through the evening, "utterly rapt, eyes shut, as though in a trance." Mitford had not noticed him.

But when they met again—as duchess and gladiator—Deborah Devonshire and Patrick Leigh Fermor struck up a friendship that has endured for more than half a century. In Tearing Haste, a collection of their letters newly available in this country, gives the impression that the conversation that started at a boating party so many summers ago has never stopped. Spanning 1954 to 2007, the volume reads like an accidental memoir of a disappearing world stretching from the manor houses of the English aristocracy to the olive groves of Greece, its people and places rendered with a kind of care that’s becoming scarce in our age of helter-skelter communication. At the same time, the book’s title, a phrase deriving from Leigh Fermor’s habit of dashing off messages "with a foot in the stirrup," captures the vigor and bustle of the lives that nourished the correspondence. I once happened upon the manuscript of a chatty letter Leigh Fermor had written in 1944 to an Englishwoman stationed in Cairo. Amusingly composed and illustrated with a witty hand-drawn cartoon, it closed with Leigh Fermor mentioning offhand that he was in hiding on occupied Crete and that an undercover runner was waiting outside to receive the communication.

In Tearing Haste is engaging from start to finish. There isn’t a dull letter among Charlotte Mosley’s selections. Even her annotations, often incorporating information from the book’s two correspondents, are as surprising as they are informative. One biographical note on the painter Augustus John includes Deborah Devonshire’s recollection of meeting him in London: "He looked me up and down and said, ‘Have you got children?’ ‘Yes.’ Another long look. ‘Did you suckle them?’" More than anything else, the collection is important as an addition to Leigh Fermor’s body of work, both because his letters constitute a larger portion of the volume and because the writing in them harmonizes with the books that established his literary reputation. But let it be said that the Duchess of Devonshire is no slouch either. Her letters, though generally shorter and less frequent than Leigh Fermor’s, share his wit and many of his interests—a fascination with language, for example, or with the byways of English and European history. She puts a charming twist on these topics while adding a few bright threads of her own to the correspondence.

Deborah Devonshire’s books—beginning with The House (1982) and The Estate (1990)—focus largely on the management of Chatsworth, the massive estate in Derbyshire that she and her husband put into charitable trust and opened to the public in 1981. (The house was a stand-in for Mr. Darcy’s Pemberley in a film adaptation of Pride and Prejudice, and throughout the letters Leigh Fermor refers to it as "Dingley Dell," after Mr. Wardle’s house in The Pickwick Papers.) As a writer, she is best when describing the seasonal rhythms of country life (the arrival of the year’s pullets, say) or assessing the gamut of rural arts (from drystone walling to mushroom gathering) and tilling their linguistic soil. In Counting My Chickens, a collection of notes and essays published in 2001, she remembers leaving Leigh Fermor "stumped" by the meaning of words gleaned from the glossary of a pamphlet about sheep. "One sheep disease," she recalls, "has regional names of intriguing diversity: Sturfy, bleb, turnstick, paterish, goggles, dunt, and pedro all are gid." On the same page she can be found rhapsodizing over "the glorious language of the 1662 prayer book, with its messages of mystery and imagination."

She takes any opportunity to undercut the preconceived notions one might have about a duchess’s likes and dislikes. "I buy most of my clothes at agricultural shows," she says in Counting My Chickens, "and good stout things they are." For the playwright Tom Stoppard, who contributed an introduction to the book, this was one of her most characteristic revelations. For me, a close runner-up is her discussion of flower gardening on a grand estate, where she admits, "I prefer vegetables." Many of her stories turn on a similar blend of unexpected rusticity and unflagging old-school civility. In an essay about the life the Mitfords led for a time on the island of Inchkenneth in the Hebrides, she describes traveling by train in the company of a goat, a whippet and a Labrador back to her sister Nancy’s house in Oxfordshire when the war broke out. "I milked the goat in the first-class waiting room," she confesses, "which I should not have done, as I only had a third-class ticket."

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For all her modesty, the duchess isn’t embarrassed to mention boldface names that have sailed in and out of her social circle. (They range from Fred Astaire to the Queen Mother, the latter called "Cake" when she appears in the letters.) The humor in one anecdote depends on knowing that John F. Kennedy was intimate enough with the duchess to employ her nickname. This caused some confusion when her uncle Harold Macmillan, then prime minister, found himself involved in a telephone conversation with the American president about matters involving Castro, SEATO and NATO. It took him a moment to switch tracks when Kennedy asked, "And how’s Debo?" (Evelyn Waugh, a friend of hers, might well have written the scene.) In the letters, Kennedy is counted among the "bodies to be worshipped," and several entries describe the friendship that developed between JFK and the duchess in the years between his inauguration and his death.

Her relationship with Leigh Fermor has many dimensions, its ardor fueled by humor, charisma and delight in a good tale. The revealing joke that runs through In Tearing Haste is that Devonshire is not a reader and that despite her lively correspondence with Leigh Fermor, she can’t manage to read his books. She praises one of his letters not for its vivid language but because it has instructions about which parts to skip. Leigh Fermor takes revenge in another letter, marking a set of passages with notes "don’t skip" and "ditto." The bit he wants her to see—a foray into history by way of language—might well have been lifted from one of the books that made him famous: "The inhabitants are Koutzovlachs who speak a v. queer Latin dialect akin both to Rumanian and Italian. Some say they are Rumanian nomad shepherds who wandered here centuries ago with their flocks and never found their way home again. Others, more plausibly, say they are the descendants of Roman legionaries, speaking a corrupt camp Latin, stationed here to guard the high passes of the Pindus, miles from anywhere."

When Waugh sent the duchess a copy of his biography of Ronald Knox in 1959, she was pleased with his personal inscription but put the book down without delving further into its contents. It was a guest who finally flipped through the pages, only to find, as a letter to Leigh Fermor records, that they were "ALL BLANK, just lovely sheets of paper with gold edges & never a word on one of them. That’s the sort of book which suits me down to the ground. Good Old Evie." Years later she listed this custom edition among her "unstealables"—books so precious she hoards them in her room to deter casual theft by her guests—along with other Waugh books, "with pages covered in print, dash it." Even the books she does admire help to cultivate the anti-literary stance. "Most precious," she says in Counting My Chickens, "is The Last Train to Memphis: The Rise of Elvis Presley. If that goes, I give up." (Stoppard once gave her a signed photo of Presley and later recalled, "I’ve seldom scored such a success with a house present.") Devonshire comes by her resistance to books—or the pose—honestly. As she mentions in a letter written in 1985, Mitford family legend had it that her father read Jack London’s White Fang as a young man and found the book so satisfying he never read another. She says the same about her reading Bruce Chatwin’s On the Black Hill, but qualifies the assertion, "if it’s the fellow I think it is."

The duchess certainly hasn’t sidestepped writing of a particular sort. In a letter from 1971, she reports to Leigh Fermor: "I have written an article about Haflingers for Riding & one about the goat I liked best for the British Goat Society’s Year Book. Two publications which I feel you may not subscribe to." It was clear to Leigh Fermor, however, that his correspondent wasn’t owning up to her literary flair. When two of her sisters published volumes of autobiography in 1977, he wrote, "I wish you would write a book like everyone else, the abstention looks rather ostentatious." Knowing her proclivity, however, he added that "you wouldn’t have to read it; someone else (viz. one) would do that." The ruse seems to have worked; she has since gone on to publish at least ten books.

Leigh Fermor’s writing career began more than fifteen years before his first book appeared. In 1933, at 18, he set out to cross Europe from the Hook of Holland to Constantinople. "I would travel on foot," he decided, "sleep in hayricks in summer, shelter in barns when it was raining or snowing and only consort with peasants and tramps." He reached Constantinople a little more than a year later, but the trip did not go exactly as planned. He did meet peasants and tramps, but he also befriended at least as many counts and slept in more castles than cowsheds. It also turned out that his destination wasn’t the endpoint he thought it would be. From Constantinople he drifted toward Mount Athos and the Greek archipelago. When war broke out he served on Crete as a liaison officer in the SOE. "After the war," as Mosley explains in her introduction to In Tearing Haste, "wanderlust took Paddy to the Caribbean, Central America, France, Spain, Italy and, most often, to Greece," where he and his wife, Joan, built themselves a house in the early 1960s.

Leigh Fermor is invariably called a travel writer, often with an epithet involving the word "greatest" in some combination with "modern," "English," "postwar" or "living." The label isn’t inaccurate, but it sells the work short. His books have created an undeniably literary genre that is distinctly his own—part memoir, part history, often lyrical, always precise. Reading a Leigh Fermor book, it is almost impossible to say what is most captivating: the companionable, erudite and witty narrative voice, the minutely rendered landscapes, the spelunking in historical labyrinths (typically guided by the alluring thread of etymology) or characters who invariably display more complicated human dimensions than those encountered in travel literature.

The overall effect is novelistic. In fact, his second book, The Violins of Saint-Jacques (1953), was a novel, and this early foray into fiction, although less widely praised than his later books, reads in retrospect like an allegorical premonition of the work that followed. In the novel—which came on the heels of his account of a journey in the Caribbean, The Traveller’s Tree (1950)—a young Frenchwoman who has traveled to an island in the Antilles to serve as governess to the children of a distant cousin falls in love with the life she discovers there, a world centered on a "happy, patrician, slightly provincial minority" in some ways similar to the lingering pockets of Central European aristocracy Leigh Fermor encountered on his walk in the 1930s. Then she sees the entire culture destroyed.

A volcano wipes out the island, but its cataclysmic eruption gives a rapid-fire fictional life—like the accelerated action of time-lapse photography—to the gradual historical change, usually for the worse, that Leigh Fermor’s books are always reaching behind as they reconstruct a lost past. Other key elements of the later books are likewise anticipated by The Violins of Saint-Jacques. The novel opens on a note derived from the travel genre—"Little distinguishes the history of the small island from that of the other French Windward and Leeward Isles except that less is known about it"—and Leigh Fermor wastes no time in steering the narrative onto a track that would become familiar, turning to etymology (in this case the story of the island’s name) to unlock the puzzles of the historical past. The narrator, nearly indistinguishable from the author’s persona in the nonfiction books, meets the Frenchwoman many years later on another island (in the Mediterranean, as you might expect) and pieces together her peculiar history of loss over the course of several prolonged evening conversations supplemented by her old sketchbooks.

When the woman finishes her tale, the narrator tries to console her by explaining that fishermen in the Caribbean have told him they regularly hear the sound of violins rising from the channel where the island once lay. They don’t associate the ghostly music with the island itself or know anything of the woman’s story, but their legend reassures her that the world she knew, though obliterated, is not gone without a trace. The sentiment that suffuses The Violins of Saint-Jacques is one that recurs in Leigh Fermor’s subsequent books—fascination with a world that has disappeared yet never ceased to exist at some submerged, or subconscious, level. Saint-Jacques is less Atlantis than Combray.

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A comparable atmosphere of nostalgia—whether for his own past or the fading history of a culture he’s exploring—pervades Leigh Fermor’s later writing, turning his books into "travel literature" as it might have been written by Proust (if Proust had gotten a good deal more fresh air and plenty of vigorous rural exercise). There is an elegiac quality, in particular, to the two volumes that are the touchstones of Leigh Fermor’s career. A Time of Gifts (1977) and Between the Woods and the Water (1986) describe the first two stages of the epic meander he took across Europe nearly half a century before the books were written. Near the end of A Time of Gifts, Leigh Fermor has traveled as far as the Danube, and he describes his impressions of standing on a bridge spanning a point in the river marking a border between Czechoslovakia and Hungary. The episode begins in the voice of an observant and literate young traveler describing the scene around him: "The masonry of the piers below sent green Ophelia-like tresses of waterweed swaying down the current. Upstream, the water broke up the reflected turquoise of a sky full of dishevelled cirrus clouds."

But as the young Leigh Fermor watches the river rush between the structure’s girders on a journey that will eventually take it through the Iron Gates gorge on the lower Danube (where the second volume on his journey will wind up decades later), the narrative offers a glimpse of its double consciousness. With storks wheeling overhead in mid-migration and a crowd of people in the midst of their own lives "strolling and hobnobbing all along the waterfront," Leigh Fermor becomes overwhelmed by the fullness of the experience. "There was much going on: in the air and the sky on the river, along the banks; almost too much." It is as if the author has been overwhelmed by memory as he writes this passage. And it is his voice, the older writer’s, that eventually emerges.

I found it impossible to tear myself from my station and plunge into Hungary. I feel the same disability now: a momentary reluctance to lay hands on this particular fragment of the future; not out of fear but because, within arm’s reach and still intact, this future seemed, and still seems, so full of promised marvels. The river below, meanwhile, was carrying the immediate past downstream and I was hung poised in mid-air between the two.

The "fragment of the future" is a fragment of the past by the time Leigh Fermor gets around to telling the story, and it is a signal of his powers as an imaginative, rather than simply descriptive, writer that he is able to re-create—and inhabit along with us—the moment as it existed forty years earlier, with its poignantly transitional atmosphere only heightened by the retrospective nature of the endeavor. It’s as if we feel the moment on the bridge because Leigh Fermor unmasks himself as the author in the present, looking back at the solitary image of himself in the past, so that the narrative hangs in midair, bridging the two points in time and charged with the mixed emotions of each.

But if backward glances tinge his books with melancholy, the mood is counterweighted by his obvious excitement at piecing together the jigsaw pieces of history, typically while relishing a given locale’s food and drink and singing the local songs. What he says in Roumeli (1966) of his wartime allies applies equally to him: "The Cretans see life in tragic and heroic terms. This being so, it is fortunate that their feeling of comedy is also pronounced." Capturing the mixed emotions that charge our experiences—whether we are at home or on the road as he so often is—may in fact be what Leigh Fermor does uniquely well.

The bracing effect of this complex synthesis is visible even in his prose. Ben Downing, one of the writer’s most eloquent supporters in American literary circles, describes Leigh Fermor’s writing as "at once exquisite and offhand, sweeping yet intimate, with a cadence all its own." The observation points to a broader fact about the scope of the books: Leigh Fermor simply does not draw boundaries between his various spheres of interest. In the books about his journey across Europe, he starts out on foot like a kind of gypsy scholar, but he winds up sleeping in castles and burrowing into the libraries of Central Europe’s dwindling aristocracy. When circumstances leave him roughing it with swineherds and gypsies, he appears no less happy pocketing an obscure dialect phrase plucked from a campfire conversation. And the persona who takes such turns cheerfully in the books is, by all accounts, a more or less unaffected representation of the man himself. Describing Leigh Fermor’s sojourn in Cairo during the war, Artemis Cooper—who edited his essay collection Words of Mercury (2003) and is now at work on what promises to be a landmark biography—writes, "Leigh Fermor could quote poetry in several languages, and sing ‘It’s a Long Way to Tipperary’ in French and Arabic. The loyalty and affection he inspired in the Cretans attested to his soldierly virtues; but these were masked by the romantic ebullience, half Byron and half pantomime pirate, which enchanted his friends."

The effect this multifaceted personality has on strangers is evident throughout the In Tearing Haste correspondence. When in 1961 Leigh Fermor was staying in a gloomy, threadbare hotel in Bordeaux, he did what came naturally, and began reciting poetry to the maid—"a tall fair sad beauty, no makeup, in a severe black dress and starched white apron"—who helped him carry in his luggage. "Peering into the rainy square," he recalls, "I quoted two lines of Verlaine about the monotonous noise of the rain, which she promptly continued for several more lines. She turned out to be enormously well read, from Paris, lonely and gloomy in Bordeaux." The two spend the evening together at a nearby bar, and when they part company, they exchange a farewell wave behind the backs of the other maids.

There are similar incidents in Leigh Fermor’s books, and the source of their vitality is less an erotic spark shared with a stranger than a literary bond. The most striking example comes in A Time of Gifts, where Leigh Fermor remembers the morning in 1944 when he found himself reciting Horace in a cave with a view of Mount Ida. Along with William Stanley Moss and a party of Cretan resistance fighters, Leigh Fermor had just kidnapped Maj. Gen. Heinrich Kreipe, who commanded one of the German divisions then occupying Crete. After waylaying his staff car at a hairpin turn outside Heraklion (there is a monument on the spot today), Leigh Fermor and his party spirited the general through a series of checkpoints and up into the mountains, from where they would make their way to the sea and finally on to Cairo. It was hard traveling, and the general was not favorably disposed toward his captors. But as dawn broke outside the cave that morning, Leigh Fermor overheard Kreipe reciting in Latin the opening stanza of a poem he recognized as Horace’s "Ode 1.9." Leigh Fermor carried the recitation through the remaining five stanzas. "The general’s blue eyes had swiveled away from the mountain-top to mine," he recalls, "and when I’d finished, after a long silence, he said: ‘Ach so, Herr Major!’ It was very strange. As though, for a long moment, the war had ceased to exist. We had both drunk at the same fountains long before; and things were different between us for the rest of our time together."

What’s so satisfying about In Tearing Haste is the way Leigh Fermor’s letters reanimate episodes and characters, allowing their story lines to spill beyond the confines of his books. In 1972 Leigh Fermor was reunited with General Kreipe for a television program, and after the broadcast the two men joined a group of Leigh Fermor’s old Cretan allies at a nearby taverna. As he described the evening in a letter to Devonshire that May, it might have been a reunion of schoolmates rather than former enemies: "Lots of Cretan songs and dances, a few German folk songs sung by the General and me, after much wine had flowed." When local journalists heard what was going on, they crashed the party. "One asked the General how I had treated him when he was my prisoner in the mountains and the Gen said—wait for it!—most energetically: ‘Ritterlich! Wie ein Ritter‘ (‘Chivalrously! Like a knight!’)."

The story bears out a notion that runs like a spring beneath all of Leigh Fermor’s books: there is a deep culture (albeit a disappearing one) of literature, art and civility—and a shared history evident in the thickets of etymology—that transcends both time and national borders. The upwelling of emotion Leigh Fermor describes on hearing General Kreipe has as much to do with that larger connection as with the praise itself, and the feeling only deepens when Frau Kreipe, a few days later, says, "You’re just like my husband told me you were all these years."

Not all the reunions Leigh Fermor recounts in the letters were so cheerful. On a trip to Hungary in 1985, he tracked down an old friend from the period described in Between the Woods and the Water. Elemér von Klobusiçky, who is called István in the book, was in his early 30s when Leigh Fermor met him, a man "at the height of his vigour"—tall, cultivated and "a virtuoso at all he took up." Those qualities held the younger traveler in his gravity for as long a period as any stop on his journey. But on this later occasion Leigh Fermor found István in an old folks’ home. Drawn and nearly toothless, he was still recognizably himself, but the recognition ran only one way. "When I said ‘I’m on my way to Greece’ he said again and again, ‘In Greece lives my old friend Leigh Fermor. Greet him from me."

In a correspondence spanning half a century, the effects of aging are bound to register, and Devonshire and Leigh Fermor can be overheard joking about "Admiral von Alzheimer" and "Dr Oblivion." The writers lament the loss of a great many of their friends, including their respective spouses. But the collection also suggests that the two of them—now in their 90s—have remained remarkably unhindered by the ravages of time. In one captivating letter Leigh Fermor, then just a few weeks shy of his seventieth birthday, writes almost breathlessly to Devonshire to report accomplishing a feat that stands as a kind of capstone to a philhellene’s career: swimming across the Hellespont, as Lord Byron did in 1810. "So here I was, about a mile S.W. from Leander’s and Ld B’s crossing places, a mile N.W. of Xerxes’ and Alexander’s boat-bridges, on the track of the Argo on the way back with the Golden Fleece and next to Troy; but too concerned about the current to think of all this, except in fitful snatches."

The letter hints at the companionable style with which his books navigate the currents of history and literature. Clearly proud of his achievement in the Hellespont’s fabled waters, Leigh Fermor nonetheless passes his swim off with a characteristic shrug, but one that seems to conceal a self-deprecating wink at the long, slow career of a writer whose attainments in the genre he perfected will certainly never be matched: "I had beaten all records for slowness and length of immersion; a wreath no future swimmer is likely to snatch at."