Stamp collecting, or philately, popular worldwide hobby. The first postage stamps were issued in England on May 1,1840. The first in the United States appeared in 1847, and by 1860 most countries had adopted the prepaid postage stamp system. Today stamp catalogs list more than 200,000 items. Serious collectors, who generally specialize in particular countries, periods, or themes, make a close study of each stamp's paper, ink, printing method, perforations, cancellation, design, information content, and historical occasion. Stamps can also be a good investment; large sums of money have been paid for rare specimens.