Philately is the study of revenue and postage stamps. This includes the design, production and uses of stamps after they are authorized for issue, usually by government authorities, the most common one being postal authorities. Although many equate it with stamp collecting, it is a distinct activity. For instance, philatelists will study extremely rare stamps without expecting to own copies of them, whether because of cost, or because the sole survivors are in museums. Conversely, stamp collecting is the acquisition of stamps, at times without regard for origin or usage.