Error notes continue to carve an ever larger niche in paper money collecting. This edition of the definitive reference allows advanced collectors to recognize the value in their holdings and still permits members of the general public to identify potentially profitable notes encountered in circulation. The entirely revised and long awaited 4th edition offers more than 550 photos and values in four grades,making identification easy. Chapters are arranged according to the actual production sequence within the Bureau of Engraving and Printing (BEP) providing a logical flow to the arrangement. In addition, historic photographs from the BEP offer a fascinating glimpse into currency production during a bygone era, contrasting sharply with the advanced technology currently in use.