Potatoes fall into three groups. Boiling potatoes are relatively high in moisture and low in starch. These waxy potatoes hold their shape when cubed or sliced, so they are chosen for potato salads, gratins, and stews. Baking potatoes are low in moisture and high in starch. When cooked, their flesh is dry and fluffy, exactly right for baking, frying, and mashing. Baking potatoes also give body to soups, as they fall apart in cooking. All-purpose potatoes, typically roundish, usually with a dull brown skin, are moderate in moisture and starch content and good for any cooking method.