The study and collection of coins and currency is called numismatics. Numismatics involves the study of the history, production, and usage of coins, paper currency, tokens, and other related objects. Numismatists, or coin collectors, often collect coins and currency for their historical or artistic value, as well as for their potential investment value. The field of numismatics also includes the authentication and grading of coins, as well as the study of coin-related literature and artifacts.