THERE'S NO BAD WAY to crack a steamed crab, but neither is there any very good one. Mother Nature has hidden the fine sweet flesh of the "beautiful swimmer" within a labyrinthine fortress because she knew that otherwise we'd eat Callinectes sapidus into extinction.

But picking the lock on this prickly little treasure chest is nothing like so hard as it looks. The rascal has a zip-strip and a pop-top, and the only tool you really need is a mallet or whatever for cracking the claws.

Professional crabpickers and a few obstinate amateurs use a paring knife to cut open and clean out crabs, but then some people eat fried chicken with a knife and fork. Crabs come with lots of sharp edges, and the last thing you need is something else to cut yourself with.

All you need is a positive attitude, plenty of old newspapers and new paper towels and a vast icy mug of the beverage of your choice (beer is traditional, but wiser over the long haul is lemonade or ginger ale). There should be a bowl of boiled shrimp or something handy to help keep up your strength; that's why crab houses keep saltines on the tables.

On the side set you out a dish of white vinegar, either plain or tinted russet with Tabasco sauce or orange with crab-boil mixture (or, if you must, the cayenne-peppered salt widely sold hereabout as "crab spice," mainly by people from Maryland, who don't know any better). This is to soak the cracked claws in, and to dip the occasional backfin lump, the better to refresh the palate after you've gotten far enough into the feast that the delicate flavor begins to seem bland.

And a feast it should be, because cracking the first crab gets you just as messy as cracking a dozen, so go whole hog. It is a scientific fact that even a jumbo crab has less than one calorie, and then only if you eat the shell. What sometimes makes you feel a little full after picking only a bushel or two of crabs is salt burn or spice bloat, brought on by eating crabs cooked Maryland style: a) oversalted, b) overspiced, and c) overdone.

But before you can get crabs inside you, you've got to get inside the crabs. Here are the keys to Crab Heaven:

1. Twist off the two big pincher claws, nibbling off the little tufts of meat that come away from the shoulder socket. Break the claw at the elbow and snap the upper arm between your fingers or crack it with a mallet (the handle end of a table knife works just as well). Suck out the meat, ignoring what doesn't come out readily, because we don't have time to fool around here. Crack the mitt end of the claw; with a little practice you'll be able to get the mitt meat out with one pincher as a handle, like a Good Humor bar. Put the claw meat to soak in the vinegar, the longer the better.

2. Lay the crab on its back and lift the pointed end of the zip-strip (or the triangular apron, in the case of a female). Wrench it free from the beast, which will create the next point of attack. Stick your thumbs in there and pry the body off the top shell, trying not to spill the delicious juice therein, which should be drunk off with a flourish.

If it's a prime crab, the points of the shell will be packed with something that feels like soft putty; it's fine-textured crabfat, which is even more delicious. In fact everything in the carapace that isn't crunchy is delicious, including the innards, although most people just discard the top shell, so fastidious have we the people become.

What now lies before you is a topless crab, little legs all asprawl. What? You pulled off the little legs? Where did it say to pull off the little legs?

3. Legs or no, we gotta get rid of the gills now. They're the feathery gray ooshy things, and you can just wipe them off the carcass with your fingers; also break off the remaining mouth parts. The curly ooshy things in the center of the shell are guts, and they're good too, especially when they're larded with more of that great gray green-greasy to yellow fat. Suck 'em, shake 'em or scrape 'em out.

Don't be shy or worry about gross noises. We are not dining, we're picking crabs. Keep your tongue and teeth going, and don't waste time wiping your chin. I have cracked crabs with Miss Manners, and she said it was okay.

4. Now we're down to the inner fortress, the castle-keep where all that fine white meat hides. Place your thumbs on either side of the zip-strip groove and press until the carcass cracks in two. Nibble up the loose meat. Notice how the partitions of the inner shell fan out from the leg sockets. If you haven't already ripped off the legs, they'll now serve as handles for the little fans of meat that remain attached at the leg sockets as you break the shell apart along the partition lines. The mother lode is the backfin lump, which stands up on the swim-fin like a mop on a short handle.

5. Try to figure out who stole your claw meat.

6. It wasn't me. Can I have your top shells?

Hank Burchard learned about crabs from his late father, a reformed Marylander.