IT was love at first sight. Henry James was 26 when he crossed the border from Switzerland and made his way, on foot, down into Italy — “warm & living & palpable,” as he wrote ecstatically to his sister on Aug. 31, 1869. The romance kindled that day lasted nearly 40 years, and played a significant part in his career; he set some of his greatest works in Italy, including “Daisy Miller,” “The Aspern Papers” and “The Wings of the Dove.”

All three are excellent traveling companions, particularly if you’re en route to Rome and Venice — but a more direct (though of course inescapably Jamesian, and therefore at times convoluted) expression of his contagious passion for what he declared to be the “most beautiful country in the world” can be found in his travel writing.

Henry James as tour guide? He won’t lead you step by step, waving a pennant so you don’t get lost, but he does show the way. His fine, reverberating consciousness sets off a corresponding reverberation in the sympathetic reader, who can’t help but admire the way Italy liberates an appetite for sensual experience in this most cerebral of authors.

If you’re thinking of visiting Umbria and Tuscany, James has even thoughtfully planned out your route: in 1874, when his Italian romance was in its infancy (and the Kingdom of Italy was a newborn nation, having achieved unification only in 1861), James wrote for The Atlantic Monthly a travel essay called “A Chain of Cities,” in which he describes his springtime wanderings in Assisi, Perugia, Cortona and Arezzo, ancient hill towns well stocked with artistic treasures and expansive views — all neatly arranged within easy distance of one another. James, traveling by train, lounges and loafs along the way, examining and judging an artist’s work, or sitting on a sunny bench beneath the ramparts of a ruined fortress, or strolling aimlessly, merely savoring the flavor of “adorable Italy.” A 21st-century traveler whose schedule is fixed by the tyranny of airline reservations may be tempted to pick up the pace (certainly a possibility if you’ve rented a car), but accident and adventure, the kind of chance encounter that loitering invites, are just as important, in the search for the essence of a place, as methodical contemplation.

James’s principal interests are scenery and art, though he occasionally casts his eye — while holding his nose — on the unwashed populace (the Puritan in him was shocked by the Italian peasant’s indifference to soap). All four towns are perched high and blessed with stunning views, but of course the views were even more gorgeous in the 19th century, before the valleys were streaked with highways, dotted with factories and warehouses and veiled by smog.

In Assisi, James looks out over “the teeming softness of the great vale of Umbria,” and watches “the beautiful plain mellow into the tones of twilight.” Today the plain is still “teeming” (though with human activity rather than nature’s bounty), and the mellow haze in the distance looks suspiciously chemical. But if the views are less pristine, the art and the architectural monuments are far more accessible, preserved and curated with care and intelligence. Each of these towns is home to more masterpieces than you can comfortably absorb in one visit; this is an itinerary overflowing with artistic riches.

If James insists on a measured tempo (in Perugia he warns that a visitor’s “first care must be to ignore the very dream of haste, walking everywhere very slowly and very much at random”), at least part of the reason is that in these towns there’s little choice. Most of the streets, especially in Assisi, Perugia and Cortona, are steep, narrow and crooked; haste would soon leave you panting. Arezzo is gentler, but there, too, James is right: even if you’re fit enough to race along, a leisurely stroll is infinitely more rewarding when nearly every building has half a millennium of history attached to it.

In Assisi, James counsels, the visitor’s “first errand” is with the 13th-century basilica dedicated to St. Francis. The church, which houses the saint’s tomb — “one of the very sacred places of Italy” — is a magnet for religious pilgrims. James hits on a suggestive metaphor for the basilica’s astonishing structure: it consists of two churches, one piled on top of the other, and he imagines that they were perhaps intended as “an architectural image of the relation between heart and head.” The lower church, built in the Romanesque style, is somber, cave-like and complex, whereas the upper church, a fine example of Italian Gothic, is bright, spacious, rational. (Though he often favored head over heart, reason over emotion, James was a master at turning the tables.) Both churches are famously decorated with frescoes hugely important to the history of art, most of them traditionally ascribed to Giotto (c. 1267-1337). Studying them closely, James pays tribute to the artist’s expressive power: “Meager, primitive, undeveloped, he is yet immeasurably strong” — a judgment still valid today.

Having trained his eager eye on these masterpieces, James saunters off to explore a palpably ancient town (“very resignedly but very persistently old”) that no longer exists. Assisi in the 21st century is pleasant and pretty, but fixed up and licked clean — after the damage from a 1997 earthquake — and wholly focused on the business of accommodating tourists and pilgrims (which seems mostly to involve selling them ice cream and religious knickknacks). James especially likes the ruined castle perched above the town, which is happily unrenovated. But he came along too soon to have glimpsed the curious monument erected, so to speak, on the steep road up to the fortress: a wire fence lovingly decorated with the discarded chewing gum of countless bored kids on their school trip to Assisi. It resembles a modernist sculpture, an abstract, folk-art Giacometti stretched along the path. I like to think of James pondering the meaning of this bizarre masticated tribute to modern adolescence.

IN Perugia, James admires the extravagant view (“a wondrous mixture of blooming plain and gleaming river and wavily-multitudinous mountain”), and picks a fight with the city’s leading artist, Perugino (1446-1524), whose paintings are graced with serene figures that seem to James just a little too serene and neat — too “mechanically” produced.

Although his report on this “accomplished little city” is lively and evocative, it’s possible that his preoccupation with the artist and the creative process distracted him from his travel writer’s duty to give the reader a distinct taste of a particular spot, and somewhat distorted his judgment. He may have overplayed his delight with the view, saying that he preferred it to “any other visible fruit of position or claimed empire of the eye” (strained phrases that smack of hyperbole). He pits the painter against the prospect, then pronounces his verdict: “I spent a week in the place, and when it was gone, I had had enough of Perugino, but hadn’t had enough of the View.”

The trick, of course, is not to spend an entire week in Perugia. It’s a fascinating place, defined by the contrast between the broad, elegant Corso that runs through the center of the town like a super-wide catwalk, purpose-built for people-watching, and the tortuously cramped streets that roller-coaster around it in an exhausting topographical tangle.

A map is essential here, but you’ll get lost anyway, defeated by the twisting, the turning, the dipping and the climbing. James’s description is peppered with adjectives that paint a grimmer picture than one sees today (he writes of “black houses … the color of buried things”), but even in this tidied-up era the medieval sections of Perugia retain their “antique queerness.”

Two days in Perugia is plenty, unless you disagree with James about Perugino, in which case a third day might be necessary, if only to visit the church of San Pietro, an oasis of tranquillity just below the city walls where hidden away in the sacristy there are five tiny Peruginos well worth the detour — and to revisit both the Galleria Nazionale dell’Umbria, where Perugino plays a starring role, and the Collegio del Cambio, which he decorated. The latter is the moneychangers’ guildhall, and it can safely be said that no financial institution has ever bequeathed a more pleasing monument to posterity than the room Perugino created with his wonderfully calm and graceful frescoes.

Cortona, which James calls “the most sturdily ancient of Italian towns,” is even more narrowly up-and-down than Perugia. A small town with a comically higgledy-piggledy central piazza, it’s like Assisi these days: in danger of seeming quaint or cute instead of beautiful or picturesque. But it’s calm, quiet and dignified (at least during the off-season), and if you set off for a ramble in any direction, you’ll pass several charming churches before you’ve reached the town’s well-preserved ramparts and registered the welcome shock of yet another panoramic view.

Arriving on a festival day, James saw neither the interior of Cortona’s churches nor its museums. He expresses mild, passing regret (“the smaller and obscurer the town the more I like the museum”), before turning to the serious business of loafing. Had he known what he was missing, he might have extended his stay. The town’s artistic treasures, now stored in the Museo Diocesano, include a handful of muscular and disturbingly odd paintings by a brilliant native son, Luca Signorelli (c. 1445-1523), and a glorious Annunciation by Fra Angelico (c. 1395-1455), one of the most delicately enchanting paintings of the early Italian Renaissance. In the valley below, you’ll see the dome of a perfectly proportioned 15th-century church, Santa Maria delle Grazie al Calcinaio.

By the time he reaches Arezzo, James has surrendered entirely to the charm of Tuscany. He mentions the museum, the “stately” duomo, and the “quaint” colonnades on the facade of Santa Maria della Pieve, but only in passing, in an apologetic aside, as if he knew that in the neighborhood there were monuments and artworks of importance to be studied, but, really, he’d rather just lounge around near the ruined castle that sits at the top of the town, just as he did in Assisi and Cortona, and sop up the “cheerful Tuscan mildness.”

No one who has visited Arezzo on a warm day in late spring can blame him — the settled, unforced, somehow inevitable beauty of the place demands unhurried, disinterested appreciation — though some would prefer to while away the hours in the lovely Piazza Grande, a sloping, comfortably enclosed space not unlike Siena’s famous Piazza del Campo, only more intimate.

The spectacle of Henry James morphing into a lazy, contented, “uninvestigating” tourist — especially after his strenuous intellectual engagement with Giotto’s frescoes in Assisi and Perugino’s in Perugia — gives “A Chain of Cities” a very satisfactory narrative arc. But as is so often the case, a pretty shape comes at a price: James leaves out any mention of Arezzo’s most famous work of art, “The Legend of the True Cross,” a cycle of frescoes in the Basilica di San Francesco by Piero della Francesca (c. 1415-1492), which today’s guidebooks insist is the town’s principal attraction.

There’s no evidence that James ever saw “The Legend of the True Cross” or formed an opinion of the artist’s work (Piero’s name doesn’t crop up in James’s oeuvre, or in his correspondence), but having come this far in his company, it seems only appropriate to fill in the blanks — to add another link to the chain — and imagine James’s reaction to this rich pageant.

In Assisi, the result of his communion with Giotto was “a great and even amused charity,” a gentle mood of indiscriminate benevolence. Here, in the hushed choir of San Francesco, he would have recognized a great artist’s bold technical advances (Piero was pioneering in his use of light and perspective), and marveled at the sleepwalker’s trance that gives Piero’s figures an ethereal spirituality even in the heat of battle. He would have envied the scope of the achievement, the variety of the scenes and the harmony of the overall composition. And he would have stumbled out into the handsome streets of placid Arezzo with his own artistic ambitions inflamed.