AT a glance, Barcelona's Inopia doesn't look like a place where you'd want to spend much time. More a bar than a restaurant, it's impossibly bright, with white walls and bare fluorescent fixtures. The room is small, irregularly shaped, and  save for one table that's reserved for large groups  there is barely any seating. Almost everyone manages with stools, or leans or stands  some outside, having ordered through the window.  Sounds like a recipe for disaster, doesn't it?  Well, let me tell you about the food: Inopia (Tamarit, 104; 34-93-424-52-31) offers the classic stuff of Spain  especially, but not exclusively, Catalonia. That means superb, even precious ingredients, prepared and served simply. The anchovy fillets are insanely good, and an aficionado could polish off a couple dozen. (So what if they're 1.7 euros each? So are oysters.) There are tomato salad with fresh salt cod; Jabugo ham; sliced confited tuna belly; and an extraordinarily creamy cheese (torta Cañarejal) that will destroy any notion of Spain being anything less than the equal of France.  There is nothing at Inopia  which opened last April  that is not at least intriguing. The plates of olives include the tiny, strikingly complex malagueñas. You can order ham croquettes in any tapas bar, but here they are made with jamón Ibérico, and they are vastly superior. In fact all the fried food  artichokes, sardines, potatoes (served with aioli and a lovely little house-made hot sauce)  is just incredible. The frying is done in olive oil, as it is throughout the best places in Spain, and it makes you wonder why  except for expense  this isn't always the case.  The menu is huge (in the style of many tapas bars, a percentage of the menu is devoted to pricey canned goods; more on this in a minute), and getting through it in one visit is hopeless. Actually, if you manage to get the reserved table, you have a shot, because for the 35-euro prix fixe menu, about $48 at $1.37 to the euro, you will be served until you beg the kitchen to stop. Without the prix fixe you will have trouble spending that much money, especially since there is good wine at 2 euros a glass.  The crowd is drawn not only by the food but by the fame: Inopia is run by Alberto Adrià, the younger brother and partner of Ferran Adrià, at this point perhaps the best-known chef in the world. In the summer, Alberto is the pastry chef at El Bulli, about 100 miles northeast of Barcelona, where Ferran is head chef, and his work there remains brilliant. But in Barcelona, in the increasingly hip neighborhood of Sant Antoni, he seems freer, happier and more at home, and he and his partners have created a restaurant that draws locals, friends, chefs and people from all over town (and increasingly the world). Lines form outside the door, but you can eat early, perfect for norteamericanos who don't want to wait until 9 p.m. for their first bite.  La Clara (Gran Via de les Corts Catalanes, 442; 34-93-289-34-60) is a different story entirely. You can sit in absolute comfort, at a table set with white linens, with attentive servers changing your plates and silverware, and for about 40 euros a person, eat far beyond your fill of raciones  essentially bigger portions of tapas  of very high quality and flavor. The upstairs is sleek, bright and pleasant, not unlike trendy American bistros circa 1995. Since this is also the nonsmoking section and, to me, more attractive than the lovely but cavernous downstairs, it's perfect.  I have eaten at La Clara only once (I've had at least two visits to the other restaurants), but if it was not superb, it was very, very good. Like the ham croquettes at Inopia, the fritters of bacalao were perfectly crisp, greaseless and flavorful, an absolute joy; the tortilla (in Spain, this means omelet) with spring onion and bacalao was fresh and moist; tomatoes  with onions and tuna  were better in March than most of ours are in August. A shipment of fresh baby lamb had just arrived, so we sampled brains, kidneys and liver; the last was slightly overcooked by my standards, but the first two were as good as they can be. Some baby goat ribs rounded things out nicely.  The above list only hints at what La Clara has to offer; the menu is enormous, with probably 60 to 70 offerings, and a kitchen that seems to execute them all quite well.  In a way, both Inopia and La Clara serve tapas, but in quite modern settings. Tapas, loosely translated as snacks, but far more serious than that these days, probably originated when a bartender offered a few nuts or olives with the drinks he was serving, and went on from there. (Some insist their beginnings were even humbler: that bartenders covered your wine or sherry glass with a plate to keep out the flies, and then began to fill the plate with little free offerings.)  You can see this tradition, from its simple beginnings to its most elaborate current form, at Quimet y Quimet, perhaps the quirkiest restaurant I know (Poeta Cabanyes, 25; 34-93-442-31-42). A representative of the fourth generation of the Quim family works behind the counter in a space about the size of a standard living room. The walls are lined to the ceiling with bottles and cans, the bottles mostly of wine  some quite inexpensive, some unknown, some famous  the cans, of vegetables, seafood and meat.
In Barcelona, there are dozens of restaurants that are of a quality associated with the best-eating cities in the world. But these five should keep you happy for a short trip.