Nailed to the trunk of an ancient-looking tree on West Dry Creek Road is a sign that says "Slow." Around the next bend is another: "Slower." This is good advice.

After rounding a couple more bends along this sinuous road, I arrived at a place where rushing would be beside the point -- Preston Vineyards, one of the northernmost wineries in California's Sonoma County. In a region with tremendous power to seduce the senses, I had found the quintessential example.

Inside Preston's tasting room, in addition to a selection of syrahs, sauvignon blancs and zinfandels, were hearty French breads, dense pumpernickel and sumptuous olive oil -- all made on the premises. Outside, picnic areas surrounded by pomegranate, pear and persimmon trees beckoned, and when I ventured beyond, I found a boccie court and more picnic areas with more fruit trees (fig, quince and lemon). A young woman appeared from behind the trees with an armful of peppers in shades of early autumn, and when I asked what the winery did with such bounty, she explained that her father, Lou Preston, used it to make sauces and side dishes for parties at the vineyard.

"With much of the fruit, though," Francesca Preston said, pointing to the deep purple figs hanging above, "we just pick them and eat them."

When she saw my expression, she said, "It's pretty Eden-like, I know."

This Eden is little more than a 90-minute drive north from San Francisco, in Sonoma County, a 1,600-square-mile oenological treasure with more than 190 wineries open to the public. Napa Valley, its more famous neighbor, is a good deal smaller but boasts about 270 wineries. These basic facts -- along with Napa's years-long marketing campaign -- have much to do with their differences in character.

It's a matter of space. With all of the fine dining, luxurious spas and sporting opportunities available in Sonoma, it is still the country -- vast, exquisite, peaceful country. And although tourism is on the rise, the pace still feels leisurely.

Having grown up just south of Sonoma, my perception is that its character, born of farming roots, has held strong even through the recent wine boom. But when I asked Sonoma vintners to characterize the differences between the two counties, they never gave me a straight answer. They'd just laugh and say, "Doesn't Napa make auto parts?" or "Napa is a four-letter word." The rivalry remains friendly.

Sonoma is divided into 10 appellations, or growing regions, four of which hold most of the wineries: the Sonoma, Alexander, Dry Creek and Russian River valleys. Recently, I spent a weekend visiting some of my favorite haunts and discovered a few new ones along the way.

My much-anticipated first stop is Gloria Ferrer, a champagne producer about an hour from San Francisco (a bit longer from the airport). The winery is perched on a hill, and sipping a flute of one of its sparkling wines while sitting on a patio overlooking the valley feels like a reward for having arrived, a toast to the day to come.

From there, the drive north toward the town of Glen Ellen offers a taste of visual pleasures to come. If it's summer or fall, the land is a patchwork of striped green miles of vines, with stretches of tawny grass between, hills rising in the distance. Even in hot weather, I prefer open windows to air conditioning here, where the sweet, dry air is redolent with rosemary and fennel. Strands of silver tinsel shimmer among vines, keeping birds from the grapes. In winter and spring, the valley is a lush bowl of green, except where vines are bare, standing as sculptural reminders of the lode that fills our bottles. In any season, the sense of moving through a place removed, a place protected -- surrounded as it is by ancient volcanic hills -- persists.

Sonoma is often referred to as the Valley of the Moon, which Jack London claimed as the translation of the Miwok Indian name. London was one of the area's most famous and revered denizens -- and his renown is never more evident than in the Jack London Bookstore at the southern end of Glen Ellen. It's a mine of local history, and after picking up a copy of the "Self-Guided Walking Tour of Downtown Glen Ellen," I strode across the street to a stretch of Wild West-style redwood buildings to sample oils at the Olive Oil Press and eat lunch at the Cellar Cat Cafe. If I'd stayed through the evening, I could have heard a local jazz band playing under the canopy of oak trees out back. As with so many of my missed experiences in Sonoma comes the refrain: next time.

Although I prefer small wineries where the exchange between those pouring and those sipping is intimate, I find visiting bigger wineries to be instructive. I'd heard that Benziger Family Winery leads groups into the vineyards and stepped aboard. It felt a little Disney-like (trams, lots of people waiting in line, goofy comments at every turn), but I learned quite a bit about the winemaking process.

Most interesting was that Benziger has been certified as an organic grower for three years, which I was pleased to see is a trend. One of the stops on the tour was the "insectory," a garden that attracts insects who eat pests and are, in turn, eaten by birds, who thus avoid the grapes. While our guide gave us details, an iridescent green hummingbird, as if on cue, hovered over a violet buddleia. A woman in the tram whispered to her companion, "I can't believe this is all only an hour away from San Francisco."

More botanical spectacles are growing at Matanzas Creek Winery, one of the westernmost Sonoma Valley wineries. Metanzas's estate gardens, set on a hill, are dominated by mounds upon mounds of various types of lavender. It's a fragrant visit and a feast for the eyes -- during my stop, two women set up easels nearby, one painting in oils, the other in watercolors.

As I headed north through Santa Rosa and past several Russian River wineries, I drove up over a crest and down into Alexander Valley, passing at least a dozen bicyclists along the way. Once into this picturesque valley, every cyclist ahead of me pulled over at the Jimtown Store. So did I.

I was on my way to the White Oak Vineyards, but the store is hard to resist. The sign out front says, "Good Coffee and Real Food." Indeed. But that's not all. In addition to tasty breakfasts, gourmet sandwiches, spreads and dips, there are all manner of temptations. Before considering whether to buy a Mexican doll, antique mirror, dog dish, whoopee cushion or handful of candy, I found it simpler to grab a bottle of cream soda and sit at one of the small tables to watch the crowd -- slowed by heat or exertion, or just plain lulled by vacation mode -- settle in for refreshment of body and soul.

Back on the road, I headed for White Oak. For years, Napa's been focusing primarily on cabernets and chardonnays, the so-called big wines, and while Sonoma produces some of the same, it's known for zinfandels and pinot noirs, syrahs and sauvignon blancs. White Oak has won several gold medals at wine competitions in the past few years. Its 2001 sauvignon blanc and 2000 merlot were especially piquant.

There are several other fine wineries in the Alexander Valley -- Sausal, Geyser Peak and Alexander Valley Vineyards, to name a few -- but if it's anywhere near time to eat, a short dash westward will take you into Dry Creek Valley and Preston Vineyards (of fruit tree, homemade bread and boccie court renown). After a leisurely picnic in the shade of a wisteria-covered trellis, I kept postponing my departure. But once on my way, I was consoled by roads and wine: enchanting lanes shaded by mossy oak trees and red-barked manzanitas, then wonderful wines at Quivira Vineyards. Other wineries in the area worth visiting include Seghesio and Dry Creek.

The biggest town in these parts is historic Healdsburg, built around a tree-filled park, where a mix of well-heeled, straw-hatted shoppers and resting farm workers share benches surrounding a fountain. It's hard to say whether there are more cafes, bookstores or boutiques lining the square, but I always spend most of my time here wandering the aisles of the Oakville Grocery, picking up picnic fare to eat on the umbrella-shaded patio. What I didn't buy this time, but ogled, were cookbooks, locally grown peaches, candied rose petals and chocolate-covered sunflower seeds. Maybe next time.

The Russian River Valley was calling. As I drove toward my destination, Rochioli Vineyard and Winery, I remembered a story I'd heard about the omnipresent roses that line the borders of vineyards. Since they are susceptible to some of the same pests and diseases as grapevines, but show symptoms sooner, they alert vintners to possible problems before they hit the vines. A poetic fact -- roses as canaries in coal mines -- and one that was confirmed by more than one local.

As with every trip I've made to Sonoma, this one felt unfinished. If I were to rise above these roads in one of the hot-air balloons that traverse the sky, I could see that if I continued to drive farther west, over the wavelike hills of this valley, I would, in fact, reach the waves of the Pacific. It's a spare but dramatic beauty in coastal Sonoma, with Fort Ross State Historic Park to the north, Bodega Bay to the south. In the balloon, I could also see reflections of other waters: rivers shuttling canoes downstream, hot springs bubbling up from the earth, spas' swimming pools offering leisure. Maybe next time.

Allison Hoover Bartlett is a freelance writer in San Francisco.

The Benziger winery tour in Glen Ellen, Calif., leads visitors through its lush vineyards.