Most cooks know everything they need to know about bay leaves. They're not very mysterious — you don't even have to measure them. Pull a leaf out of the jar and toss it in the stew pot. Nothing to it.

Actually, there is a bit to know about this everyday herb we toss into so many dishes, especially those with tomatoes. I'll start with the trivial.

The botanical name for bay, Laurus nobilis, hints at its legendary history, which includes tales of love-struck gods and heroic rewards. Laurus is from the Latin for praise and nobilis is, of course, noble and renowned. It isn't surprising then that laurel-leaf wreaths were used to crown Roman emperors and chariot race winners.

But did you know that if you're a college graduate, your baccalaureate owes its name to the bay leaf? Way back when, outstanding Roman scholars were given laurel berries, or baca lauri, in Latin, and were called baccalaureates.

Today, the bay laurel is a tree found throughout the Mediterranean and in other moderate climates where gardeners who don't want it to grow to its full height keep it in tubs and prune it into a ball.

Bay leaves sold at the Co-op are grown in Turkey, where they are harvested in the morning to prevent an overly bitter taste. Good bay leaves should have a strong scent of pine and pepper and still be green. Old, brown leaves will have lost all their chlorophyll and most of their flavor. If you keep your bay leaves in an airtight container away from sunlight, they should last about a year. However, you may wish to buy only a month's worth at a time to guarantee a fresh supply in your cupboard, something you can't do with prepackaged bay leaves sold in most grocery stores.

If your bay leaves are strong, use them sparingly. "The Joy of Cooking" recommends only 1/6 of a dry leaf to a quart of liquid.

Bay leaves are added early in the cooking process, since their flavor doesn't dissipate the way so many herbs do. Recipes almost always require removing the bay leaf before serving, since they are tough and hard to eat, although they're not harmful if you do manage to eat one.

Bay combines well with other seasonings and is considered a supporting flavor. Its peppery, piney scent is a familiar part of Italian flavorings and many pickle recipes. It is hard to imagine a spaghetti sauce made without it.

Bay is less well known as a seasoning for fish, probably because fish is rarely cooked in liquid as long as it takes bay leaves to impart their flavor. Nonetheless, it is a delightful combination and the following recipe gets around this problem by using a bay-scented poaching liquid.

This recipe is from the excellent cookbook sold at the Co-op, "Almost Vegetarian" by Diana Shaw. Shaw's recipes excel at using spices in creative, tasty ways.

Milk-Poached Fish with Chive Cream

2 cups milk, nonfat if desired
1 large yellow onion, sliced
1 leek, white part plus 1 inch of the green, washed and sliced
1 bay leaf
¼ teaspoon crumbled dried thyme
1 ½ pounds firm white fish fillets, such as bass, monkfish or haddock
1 large egg yolk
2 tablespoons heavy cream
¼ cup minced fresh chives

In a deep skillet, combine the milk, onion, leek, bay leaf, and thyme. Heat gently over medium-low heat and let the vegetables and herbs steep in the warm milk until soft, about 45 minutes. Turn off the heat, cover and let steep 15 minutes longer.

Add the fish, then gently heat the milk over medium-low heat and poach the fish, taking care not to bring the milk to a boil. When the fish turns white, about halfway through the cooking time, gently turn the fillets with a slotted spoon. Poaching will take 6 to 9 minutes for thick fillets such as monkfish, and 3 to 4 for thinner fish such as snapper. When the fish is done — when it's opaque in the center and flaky when pierced with a fork — transfer it with a slotted spatula to a place covered with a paper towel, and cover loosely with foil.

Pour the milk through a fine sieve into a small saucepan. In a small bowl, whisk together the egg yolk and cream, and add two tablespoons of the hot milk to this mixture. Whisk well, then add 2 tablespoons more. Stir again, then pour the egg yolk mixture into the milk. Cook over low heat, stirring constantly until the mixture thickens, about 8 minutes. Be careful not to bring to a boil or the sauce will separate.

Remove the sauce from the heat and stir in the chives. Distribute the fish on serving places and spoon sauce over each serving.