They can be served warm, or cold, or room temperature like potato salad. They can be made from peeled or unpeeled potatoes.
They can be as simple a baked or boiled potato, or be more elaborate, such as Pommes de Terre Anna or Delmonico Potatoes.
Potato Dishes can be made of potatoes that are cleaned and peeled specifically for that dish, or they can be made of leftover mashed or boiled potato (such as some hashes which call for chopped leftover boiled potato.) Potato chips (aka crisps) are now considered junk food, though they were originally an elegant potato dish made fresh in the kitchen.
There are, however, no dishes that CooksInfo.com knows of which involve serving potatoes raw. The potatoes are always cooked, even if they are later to be used cold (as in a salad) in order to break down the starch.
Sweet potatoes are usually counted in the category of Potato Dishes.
Depending on the size of the potato chunks being cooked, they will need 10 to 25 minutes of boiling.
Many northern countries came to rely heavily on potatoes (and other root vegetables) as a base for food dishes because they cropped reliably in the shorter growing seasons, and also stored reliably.