Black peppercorns are the fruit of the pepper vine (Piper Nigrum). Although native to India, Vietnam produces about a third of the world's supply of pepper each year.
Black peppercorns are produced by picking the green, unripe fruit, cooking it briefly in hot water, then drying the pepper, either mechanically, or in the sun. The color of the pepper turns from green to dark brownish black as it dries.
Pepper has an ancient history, being mentioned in Indian cookbooks nearly 4,000 years ago. It was used in the mummification process by the ancient Egyptians. Wealthy Greeks and Romans used peppercorns extensively in their cuisine, to the point where during the fall of the Roman Empire, a ton of peppercorns were demanded as a ransom by Attila the Hun.
Black peppercorns are incredibly useful in cooking, lending a warm spicy note to everything from chicken stock to ice cream to the Bloody Mary.