(MONEY Magazine) – You walk into an upscale restaurant, and the waiter drops a tome as thick as a college biology textbook onto your table. Like that long-forgotten text, it's filled with foreign words and strange concepts—and you're about to be quizzed on it.

Face it: Choosing a bottle of wine off a restaurant wine list can be one of the more stressful rites of civilized life. How do you make your selection without, on the one hand, looking cheap to your client or your fiancée or, on the other, feeling that you've spent way too much? Are the priciest names on the list the only safe choices? Are they a rip-off?

To answer these questions, MONEY spoke with about a dozen wine experts and sommeliers. They shared the following benchmarks—as well as their favorite less popular wine regions (see page 150)—to help you navigate any restaurant's wine list. If you know that you want the Cloudy Bay Sauvignon Blanc from New Zealand at $60 a bottle, that's what you should order. But if you're not sure what you want or how much to spend, or you can't find a name you recognize on the list, these guidelines can help you find wines you can order with confidence.

Finding the values...

Before you can mine a list for the best buys, it helps to know a little about how restaurants price their wines. Typically restaurants charge as much as four times the wholesale price for the least costly bottles. The markup is likely to be lower on the most expensive wines on the list—which makes them good buys if the occasion (and the company) is special enough. But restaurants often mark up their most popular wines aggressively regardless of their wholesale price—high markup and high volume are a profitable combination. At Cité, for example, a Manhattan steak house that serves some 250 wines, its 50 bestsellers represent about 40% of sales, according to Kevin Zraly, who oversees the wine program at the Smith & Wollensky restaurant chain, Cité's parent.

...at a destination restaurant

Restaurants in large cities and resort areas that boast star chefs or restaurateurs usually have a sommelier or a beverage director on hand to answer questions. But it's wise to get your bearings before you call in the pro—he or she can be more helpful if you have an idea of your price range and you're less likely to feel intimidated. As you'll see from these guidelines, wine prices are generally keyed to menu prices.

ORDERING BY THE GLASS At white-tablecloth places, you'll find good wines by the glass at prices equivalent to those for mid- to high-end appetizers. Or divide the price of a bottle of the same wine by four or five, the approximate number of glasses in a bottle. "I wouldn't want to pay much more than a quarter of the price of the bottle for a glass," says Danny Meyer, who runs Union Square Cafe, Gramercy Tavern and several other top restaurants in New York City.

In fact, the less expensive selections available by the glass are often excellent. Sommeliers at fine restaurants frequently fill the lower end of their lists with unusual offerings from unfamiliar regions or producers. Try, say, a d'Arenberg Shiraz from Australia, says Andrea Immer, master sommelier and dean of wine studies at the French Culinary Institute, and "you'll get the last laugh in terms of a great value for the money."

The reason, explains Mary Ewing-Mulligan, a master of wine and co-author of Wine for Dummies, is that wines that have "the handicap of being unknown" can't command a high price. For example, Morrell Wine Bar, an offshoot of a large New York City retail wine shop, has an $11 glass of Cabernet Sauvignon from Chile; the average by-the-glass price for a Cabernet from California is $25.

ORDERING BY THE BOTTLE The sweet spot for bottles is one to two times the price of the average entrée. At Danny Meyer's Blue Smoke, a barbecue spot, the average entrée costs $18, so you can find a good value pairing for $18 to $35.

Some very top-tier restaurants have only prix fixe menus, with no entrée prices for you to use as benchmarks. In that case, aim to spend an amount roughly equal to the price of a dinner. At a place like Charlie Trotter's in Chicago, that can mean $100 a bottle, since the prix fixe menu runs $130; at Meyer's Gramercy Tavern, it's $72. Are there fine wines on these lists for less? Certainly. But most people go to the highest-end places to celebrate a special occasion, and the wine lists, like the menus, are calibrated for a splurge.

ORDERING BY THE HALF-BOTTLE Until recently, big selections of half-bottles were unusual. Now, says Smith & Wollensky's Zraly, "the cycle is back to half-bottles. Most of our wine lists are offering a lot more." But as Evan Goldstein, master sommelier and director of wine and hospitality education at wine importer Allied Domecq, notes, you won't find "super great value" in half-bottles. They cost nearly as much to produce as full bottles, and that's reflected in the wholesale price. Sometimes a half-bottle is the way to go (see "How Much Do You Need?" on page 150), but it will never be the best value per sip.

...or at a casual restaurant

At your favorite neighborhood spot or bistro, or at chains like Olive Garden and the Cheesecake Factory, a sommelier probably isn't on hand to answer questions. So keep these tips in mind.

ORDERING BY THE GLASS When you see a glass of the house red running for the unbeatably low price of $3.95, keep in mind that most restaurants expect a single glass to cover the wholesale price of a full bottle. Casual restaurants are often quick to recommend their house wines. If there is no producer listed with the Chardonnay or Cabernet—or worse, if there's no grape name, only "red," "white" or "pink"—stay away. "You won't get sick," says Ewing-Mulligan, "but if you care about what you're drinking, you won't like it."

You'll usually find better values at the higher end of the list. "They really do want to reward the person who pays $1 to $1.25 more," says Immer, who has developed wine lists for Marriott Hotels & Resorts and Olive Garden.

ORDERING BY THE BOTTLE Add $5 to $10 to the highest entrée price. At the Olive Garden in Akron, for example, the most expensive entrée is a $19 T-bone, so expect to find a good bottle for approximately $25 to $30.

ORDERING BY THE HALF-BOTTLE Expect a limited selection at all but the most ambitious casual spots. Once again, the half-bottle is rarely the best value unless you are sure you want more than one glass but no more than two and a bit.

And don't believe the myth that older is better and always deserves a higher price. Some 90% of the world's wines—both reds and whites—are meant to be consumed within three to five years of their vintage, says Wesson. It's far better to drink a wine that's a little too young than one that's a little too old.

Wherever you eat, don't be afraid to discuss your choices with your server or sommelier. "People aren't clairvoyant," Allied Domecq's Goldstein points out. "They don't necessarily know what you want to have, so you need to establish a dialogue." Good servers can steer you toward the best values that will complement your food, especially if you're ordering a porterhouse and your guest has decided on sole. It may even be that just this once the half-bottle is the wisest choice—one for each of you. Cheers.

The same glass of Chardonnay at a Manhattan restaurant can set you back $12 or $16, depending on how you order.

Prices for wines by the glass are generally in line with appetizer prices, and full bottles with entrées.