In the beginning there were clay pots. Then iron. Then aluminum and stainless steel, all in a farily narrow range of shapes and sizes. And now in cookware and department stores all over America, there are not only the plain metals we all recognize, but combinations, layers, sandwiches and metals treated so they look and act like other metals. And all in a vast range of gauges, shapes and sizes.

For lots of cooks, stainless steel was a big improvement over the old enameled steel, iron or aluminum pots they'd been using. It looked pretty, it didn't dent easily or chip at all and it didn't react strangely to and food. But it was very slow to move heat around and it heated unevenly. So manufactures started washing the bottoms of their pots with a thin layer of copper, a metal that conducts heat magnificently. That's how it started. Where it will end is anybody's guess.

Pots made of more than one metal layered or sandwiched together usually combined a fast heat conductor such as aluminum or copper with stainless steel, the idea being that the copper or aluminum conducts heat and the stainless protects the food from chemical interaction that occurs with those metals and food. The problem is that heat dislikes traveling from one metal to another (that's why handles of many pots are made of a different material from the pot itself) and that stainless is such a bad heat conductor that it tends to cancel out the good properties of the other metals.

I tried out two combination pots, one from the widely advertised "Original" Cuisinart line. In the bottom of this pan a layer of copper is sandwiched between two layers of stainless. Copper and stainless are present in about equal amounts. The bottom of the Cuisinart pot was quicker to heat up than conventional stainless, but the heat was very slow to travel up the sides since they are pure stainless. In cooking with it I found its behavior much closer to stainless steel than to copper. Its prices, however ($44 for an 8-inch frying pan), are actually higher than comparable-weight copper. A 7 1/4 inch presentation-weight copper frying pan costs around $30.

I also tried an All-Clad pot made of treated aluminum similar to Calphalon but lined with stainless. It performed more like aluminum than like stainless. The chief advantage of this combination is that the inside of the pot is shiny and easy to keep clean. The treated aluminum, even without its stainless lining, with not interact with foods. The 10-in omelet pan is about $55.

Calphalon is a brand name for aluminum pots that have been treated electrochemically so that the molecules on their surface are denser than in conventional aluminum. Calphalon doesn't react with foods like eggs and wine as regular aluminum can. Although Calphalon omelet pans are made in two gauges (or thicknesses), the lightner weight is not seen much in Washington. Other Calphalon pots and pans come only in the heavier, "commercial" weight. Calphalon is not cheap. A 10-inch frying pan (Calphalon calls it an omelet pan) is around $35, which is slightly more than conventional aluminum but less than copper.

There are various aluminum pans on the market with non-stick coatings like T-fal and Silver-Stone. These coating are perfluorocarbon resins. Food and Drug Administration literature says about these coatings: "While the resin may decompose in heating and particles may chip off, this is an inert substance and poses no health problem. FDS scientists believe that pans coated with the resin are safe for conventional ketchen use."

Black or "blued" steel frying pans are available in some stores. They are great for omelets and other things that need to be cooked quickly because they heat up fast and can take high heat. Steel pans are seasoned before they are used and will rust if they're left wet.

While you're deciding what material you want for your pots and pans, think also about their shapes and sizes. For instance, saute or frying pans come with rounded sides or straight, perpendicular sides. Straight-sided saute pans are for frying spattery things like hamburgers or chops. The ones with rounded edges, called omelet or frying pans, are useful for sauteeing small things like mushrooms or onions because you can turn the ingredients simply by jerking the pan away from you, flipping the ingredients slightly at the same time. (You can practice the motion with raw rice before you start flipping around hot mushrooms.) They are also the perfect shape for omelets, which you fold with the same fliping motion.

Saute pans with higher sides are sometimes called chicken fryers and usually come with lids. They are often used for deep-frying, but they're also good for recipes like chili or spaghetti sauce that combine sauteeing and simmering. The classic chicken fryer is cast iron, through they are available in aluminum and stainless too.

Saucepans come in several configurations. Taller, narrower shapes allow less evaporation than squatter shapes. Stockpots, for that reason, are always taller than they are wide. If you mainly cook frozen vegetables or heat up soup in your saucepans it probably doesn't make a lot of difference what their shape is or, for that matter, what the materal is.

On the other hand, many wonderful modern sauces are based on stock that has been allowed to simmer, reduce and thicken without the addition of starches. For these sauces you want a wider saucepan so more surface area will be exposed. You also want a heavy-gauge metal to avoid scorching the sauce on the bottom while it's reducing.

If I had to vote on a favorite all-around pot, it would be the fait-tout, a saucepan with straight, not curved, sides that flair gently outward. In heavy aluminum, or better yet, heavy tin-lined copper, you can saute in it, simmer in it, reduce your sauce in it, or make hot chocolate in it.

In general, unless you only use your pots and pans to heat up canned foods, the heavier gauge metal is always best. Heavier gauges are less prone to warping or denting, and they provide a more even heat.

Here are some size guidelines: A 10-inch frying pan or skillet (measured at the top) is probably the most useful size for a small family. It generally holds four hamburgers, two large, chopped onions, or half a pound of sliced mushrooms. A 7- or 8-inch omelet pan is the right size for an individual omelet.

A three-quart saucepan will hold three quarts only if filled to the brim. It is the smallest size that will fit a block of frozen vegetables unless you chop off the corners of the block first. It will hold two cans of soup. A 1 1/2-quart saucepan is a more reasonable size if you want to make a cup or two of sauce or heat up a little milk for cafe au lait.

Cast iron and steel both need to be seasoned before they can be used successfully. Rollie Zachman of Commercial Aluminum, a company that manufactures Calphalon and regular aluminum cookware, recommends that regular aluminum also be seasoned. Manufactures usually give directions for seasoning their pans. Generally, the method is to coat the pan with vegetable oil and let it heat slowly, then repeat the process. It may take weeks of occasional oiling and heating to get a pan properly seasoned. Some cooks think this is partly a mystical process of the pan and its owner getting to know one another, but really it's just a matter of giving the oil a chance to carbonize and fill up the pores of the metal, sealing it.

Seasoned pans can be rinsed under hot water and rubbed with coarse salt to clean. Some cooks never use detergent on a seasoned pan. A seasoned pan washed in the dishwasher will no longer be a seasoned pan.

Zachman recommends against seasoning Calphalon because Calphalon's hard surface doesn't allow the seasoning to sink in but instead keeps it standing on the surface where it can cause sticking.

Cookware manufacturers usually tell you to simply swirl water and a little detergent around in their pans and voila, you have a clean pan. We all know that this is not always the case. Obviously, the ideal is to never burn anything. But if you do, try to do it in Calphalon, regular aluminum or stainless steel. All of these can take the occasional abrasive cleanser. Tin-lined copper is touchier because of the softness of the tin. But if disaster does occur and soaking overnight -- or even for days -- doesn't work, a little judicious scrubbing with a metal pad does not ruin a properly tinned pan.