Clams are the underrated relative of oysters, and many people shy away from them. This is unfortunate because they come in many shapes and sizes, and they are flavorful enough to appeal to virtually anyone who enjoys shellfish. Whether eating them raw, in a stew or as an addition to a pasta sauce, clams are an interesting addition to any meal. If you know a few things about these delicacies, you can buy and eat them with confidence.

Know what kind of clam you are looking for. There are many different types of clams available all over the world, but soft-shell clams and hard-shell clams compose the two basic groups. How you plan to use the clams will determine which type you should purchase. Despite their description, soft-shell clams do not have an especially soft shell, but their flavor and shape is different from hard-shell clams. They tend to be more oblong than the rounded, darker hard-shell variety. Soft-shell clams make better steamers and can be eaten raw, although most "raw bars" serve hard-shell clams. Hard-shells are preferred for stews and chowders.

Pick closed clams when purchasing soft-shells. If you find one that isn't closed, tap it gently and watch for 30 seconds to a minute. If the shell doesn't close, discard it; the clam is dead and inedible. Many soft-shell clams also have protrusions, or tails, sticking out from inside the shells. They are safe to use.

Look for Cherrystone or Little Neck clams if you plan to eat your hard-shell clams raw. To cook them in a soup, use a larger chowder clam like the Longneck clam. Calculate about 450 grams per person when buying clams because the shells weigh much more than the meat.

Buy clams at your local fish market. If there isn't a fish market in your area, try purchasing clams a grocery store. The average price per pound will be somewhere around $4 to $10, depending on the variety. You can also order clams online (see Resources), but there's never any guarantee of what you will get.

If you buy frozen clams, keep them on hand for up to three months. These clams have been shucked, which means they no longer have their shells. Frozen clams may be fresher than so-called "fresh" clams because the frozen versions are often put on ice the same day they're caught to lock in freshness. With "fresh" clams, you have no guarantee how long they've been out of the ocean.

Try cockles. This small member of the clam family has a distinctive heart shape and you can tell if the cockles are alive the same way you would any clam. The shell should be closed when you buy them and they should open up after being steamed; otherwise they are dead. Cockles taste wonderful in an Italian clam sauce. Clean cockles as you would a hard-shell clam, and sauté them with olive oil, shallots and a cup of white wine over medium heat. Cover the pan and let them steam for five minutes. Toss with pasta. You can finish the dish with a handful of flat-leaf parsley and a dab of butter. Include a good crusty bread to soak up the cockle juice.