Scott catalog

The Scott Catalogue of postage stamps, published by Scott Publishing Co, a subsidiary of Amos Media, is updated annually and lists all the stamps of the entire world which its editors recognize as issued for postal purposes. It is published in eight large volumes (as of 2015) that include six volumes containing all the countries of the world that have ever issued postage stamps, the United States Specialized Catalog, and the 1840-1940 Classic Specialized Catalogue (covering the world for the first 100 years that stamps were issued). It is also produced in non-printable CD and DVD editions. The numbering system used by Scott to identify stamps is dominant among stamp collectors in the United States, Canada and Mexico.

The first Scott catalogue was a 21-page pamphlet with the title Descriptive Catalogue of American and Foreign Postage Stamps, Issued from 1840 to Date, Splendidly Illustrated with Colored Engravings and Containing the Current Value of each Variety. It was published in September 1868 by John Walter Scott, an early stamp dealer in New York, and purported to list all the stamps of the world, with prices for each. A notice inside does caution the reader that "it is simply impossible for any one to always have every stamp" in stock. The original catalog has been reprinted.

In subsequent years, the Scott company gave up dealing in stamps but continued to publish the catalog, gradually providing more detail as the hobby evolved and collectors became more sophisticated. In addition to the factual information about the stamps, the catalog includes price information based on market analysis and reported sales from the previous year. As of 2006, and despite annual changes to save space, the catalog was more than 5,000 pages.

The Scott numbering system assigns plain numbers for regular mail stamps, and uses capital letter prefixes for special-purpose types, such as "B" for semi-postals and "C" for airmail. The numbers are generally consecutive; there are gaps among older stamps, where some numbered types were later renumbered, and among newer stamps where Scott has left numbers unassigned in the anticipation of additional stamps in a series. If more stamps than expected appear, Scott will add a capital letter as suffix, or if the change is very recent, it will renumber stamps. Minor variations, such as shades or errors, get a lowercase letter; so the "C3a" above indicates a variation (error in this case) on what is listed as the third US airmail stamp.

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Wikipedia