A region-by-region guide.

How can there possibly be 20 different winemaking regions in Italy? Isn't the entire country just one big winemaking region? (With the room left over allotted to truffles, olive oil, pasta and cheese?) Although Italians seem able to make wine just about anywhere (in areas sanctioned or otherwise), there are actually a great many distinctions between one wine region and another, and the quality of the wines they produce. For example, two of these zones, Piedmont and Tuscany, have been turning out important wines for decades, while others, such as Sicily and Campania, are more recent entrants into the world-class-wine sweepstakes. Happily, though, almost every region in Italy now has a name worth remembering and a wine worth looking for.

This region wins all the superlatives. It's the greatest wine region in Italy and home of two of the world's best red wines, Barolo and Barbaresco. Both are made from the Nebbiolo grape. Super seconds are Barbera and Dolcetto--the wine name and the grape name. There are interesting dry whites made here, too: Gavi and Arneis from grapes of the same name. Piedmont is also the home of both Asti Spumante and Moscato. Some top producers: Altare, Bologna, Ceretto, Gaja, Giacosa, Grasso, Sandrone and Scavino.

Valle d'Aosta
The smallest wine region in Italy,Valle d'Aosta seems closer to France than Italy. French varietals (Chardonnay, Pinot Noir, Pinot Gris) are most widely and successfully planted. The wines are not commonly found in the U.S. Two notable producers: Les Crêtes and Charrère.

Trentino-Alto Adige
This Alpine region is as much German as it is Italian. In fact, German is spoken here more often than Italian. Once overlooked, it's now an emerging area, with a number of small, high-quality wine cooperatives and producers. The best grapes are indigenous reds, like Lagrein and Schiava, as well as Pinot Nero and Cabernet. Some excellent whites are also made here, especially from Gewürztraminer. Four great names: Hofstätter, Lageder, Pojer e Sandri, Tieffenbrunner.

Friuli-Venezia Giulia
This region is famous for high-quality white wines, mostly made from grapes like Pinot Bianco, Riesling and Pinot Grigio. Three great producers are Livio Felluga, Schiopetto and Jermann, which makes a pricey Chardonnay and an expensive white blend called Vintage Tunina.

Italy's best sparkling wine (méthode champenoise) is made in Lombardy, specifically in the Franciacorta district. Look for these producers: Bellavista, Berlucchi and Ca' del Bosco.

Verona (not Venice) is the wine capital of this region and the home of VinItaly, the enormous annual wine fair. Veneto's best-known wines include Soave, Valpolicella, Amarone and the sparkling wine Prosecco. In Veneto you find both giant producers, such as Bolla and Santa Margherita, and small, high-quality ones, such as Allegrini, Anselmi, La Cappuccina, Maculan, Masi and Quintarelli.

This region's chief white grapes are Pigato and Vermentino, though Pigato is thought better. Both produce bright, lively dry wines. Barrique-aged reds are made here, too. Labels to look for: Terre Bianche, Walter de Battè.

Although Bologna is a culinary capital of Italy, this region has historically been home to good, not great, wines (that's changing for the better). It is also home to Lambrusco, the fizzy red made famous by Riunite. (Lambrusco, by the way, accounts for 5 percent of the total wine produced in Italy!) Also look for Fattoria Paradiso's Barbarossa (red) and Albana (white), and Terre del Cedro Sangiovese.

One of Italy's greatest wine regions is also its most touristed. Almost all its best wines are red, the most famous being Chianti. The star grape is Sangiovese, important not only for Chianti but also for Brunello, Vino Nobile di Montepulciano and Super-Tuscans (modern-style blends of Sangiovese and grapes like Merlot and Cabernet). A few famous names: Antinori, Felsina, Frescobaldi, Isole e Olena, Castello dei Rampolla.

This region became world famous for its Verdicchio, a dry white made from the grape of the same name, thanks to Fazi-Battaglia, a huge company that used to bottle its Verdicchio in a fish-shaped bottle. The best wines are made in the Verdicchio dei Castelli di Jesi area. Top producers: Colonnara, Umani Ronchi.

This is the home of one famous red wine, Montepulciano (also the grape name), and one world-class winery, Valentini, and a lot of commercial producers.

This region's most famous white wine, Orvieto, is made around the pretty town of the same name. Another important white wine is made from the Grechetto grape. Red wines are also produced, notably, Sagrantino di Montefalco. Top names: Lungarotti and Antinori, which makes Castello della Sala.

This region is often grouped with Abruzzi because it produces similarly rustic reds from the same grape, Montepulciano. More-modern winemaking is at hand, notably at Di Majo Norante.

Like Sicily, this island has lots of big producers, though in Sardinia's case, the two biggest producers are also the best: Sella & Mosca and Argiolas. There are lots of grapes with obscure names, but the chief white grape is Vermentino; the chief reds are Cannonau and Monica.

Most famously, it's home to Rome. Almost as famously, it's where Frascati and Est! Est!! Est!!!, soft, dry whites popular in the 1970s (and much better today), are made. Fontana Candida is the biggest name, but Gotto d'Oro and (especially) Villa Simone are also notable.

The region of Naples and Capri, Campania was long a backwater in the world of wine but has made great advances in recent years. Its most important red grapes are Aglianico and Piedirosso. Important white grapes are Greco di Tufo and Fiano di Avellino. Favorite white wine of tourists: Lacryma Christi (or Christ's Tears). Look for producers Mastroberardino, Villa Matilde, Montevetrano and Feudi di San Gregorio.

Only one wine of renown is made here, Aglianico del Vulture, which is considered one of the best reds in southern Italy (it's called the Barolo of Basilicata). D'Angelo is a leading producer.

This up-and-coming wine region is mostly red (and rosé) wine territory. Its two primary grapes are Primitivo (a possible Zinfandel relative) and Negroamaro, or "bitter black." Look for producers Pervini, Sinfarosa and Cosimo Taurino, which turns out Apulia's best-known red, Salice Salentino.

The "boot" of Italy is still a fairly primitive wine region. Its white wines are made mostly from Greco, its reds from the ugly-sounding Gaglioppo. The only Calabrian wine with a measure of fame is Cirò, in red, white and rosé versions. Best-known names: Librandi, Fattoria San Francesco.

This island produces enormous amounts of wine, most of it white. There are lots of cooperatives but not many small wineries. The best-known name is Corvo, which makes lots of nonserious red and white wines and one serious red, Duca Enrico. Smaller producers winning acclaim include Planeta (working with grapes like Cabernet and Chardonnay) and Valle dell'Acate.