Athenians of the fifth century B.C. were crazy about seafood, and for interesting reasons, writes James Davidson in Courtesans and Fishcakes: The Consuming Passions of Classical Athens, a learned treatise on eating, drinking, and sex. One reason was that a marine creature did not have to be slaughtered sacrificially like a sheep or a pig, cut up into hunks of equal size, and shared with others. You could simply conk your eel and take the best part—the head—for yourself. Another reason was that seafood was irresistibly seductive.

Christos Tsardounis, a Greek American in charge of what goes on in the two-person kitchen of Aspasia, offers patrons a small, thoughtfully conceived menu that usually includes several piscatory dishes. Squid is a specialty, lightly grilled and served over a creamy hummus of chickpeas with green olives and a lemon vinaigrette as an appetizer ($8), so delicious as to make an instant convert of anyone who thinks of squid as less rewarding than a good rubber band. Tuna was a favorite of the ancient Greeks, and here it is as an entrée ($25), seared and pink in the middle, encircled by bacon and with a sesame ginger tartar, over intensely flavored lentils. The bouillabaisse of red snapper, monkfish, mussels, and clams ($22) is a marvel, for each component in the pungent broth is cooked just right. If last night you loved your bay scallops vol-au-vent with creamed leeks and roast chestnuts ($25) and have come back for seconds, you may be disappointed, for Tsardounis changes his menu often, depending on what perfect ingredients he finds at market. Instead of scallops, tonight you have duckling, or steak, or rack of lamb. (The old Athenians liked thrushes and hares, meat stews, the occasional sausage.) Perhaps the lamb is closer to medium than the medium-rare you asked for. Perhaps the truffle flan isn’t as hot as you’d like. And you might skip dessert; the sweets department is not where Aspasia shines. These are pardonable offenses. The coffee is first rate, and you can have a nice glass of port with it.

Aspasia, the place, is a newish, 35-seat bistro about a mile from Harvard Square out Concord Avenue. Its décor is unassuming, its atmosphere warm and informal. Parking is not an impossible dream. This is the first restaurant Tsardounis and his wife have run, although he has cooked in some of the most celebrated establishments in the area, including Michela’s, Olives, and Number 9 Park Street.

Aspasia, the person, was a fifth-century Athenian courtesan of famous beauty and intelligence. She was alleged to be equally capable of making droll small talk with Pericles, the statesman and patron of the arts whose mistress she was, and of influencing him to do battle with Sparta. In the days when ancient men made the lives of ancient women wretched, she was bold, like one of Tsardounis’s sauces. Her namesake restaurant is a vivid presence and a pleasure in the (Greater) Athens of America.