TODAY'S KITCHENS are like theaters. The star cook (or more likely cooks, the current tendency is to have as many cooks as ingredients) performs behind the counter at one side of the room, while all the hungry guests and family watch and applaud.

Perhaps Julia Child started it, with her laid back attitude toward dropping the dough or the cake. Anyway, now people no longer worry about sealing off the confusion and the cockroaches from the guests. People, even at a sit-down dinner with sterling place plates, want to check in to see where it all came from.

Today's kitchens are planned for multiple occupancy, not only the guests, but all the members of the family tend to pitch in to cook or kibitz. Many couples don't fuss over whose turn it is to cook supper -- they both do. Each cooks a different dish. Or one chops while the other makes the sauce.

The trend is a return to the hearth, old "keeping" room, or country kitchen.

As well as all the latest in kitchen gadgets, kitchens are likely to have such crowd pleasers as: display space for basket, plate and pot collections, ceramic tile, and light -- lots of it.

The old back door, once suitable only for taking out the garbage and bringing in the wash, has been upgraded to the garden entrance , often with sliding glass opening onto a deck, or a patio, serving as a fair weather friend.

Living looks today at six kitchens: three architect-designed, two standard kitchens installed by kitchen specialists, and one put together out of the castoffs of one of the others. The most expensive of the kitchens cost $42,000 for a completely new room with many archtiectural changes and all new appliances. The least expensive cost $1,000 with the only new elements being the paint, the cooking units, plumbing and electrical work. Two are in detached houses, one is in a rowhouse, another is in a condominum. All owners, are, for the moment, pleased, but poor.