Scott catalogue

It is published in fourteen large volumes (as of 2021) that include twelve 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).

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.

Because of its commercial importance the publishers of the Scott Catalogue claim copyright on their numbering systems, and grant only limited licenses for their use by others.

[1] Editors of this, the dominant catalog in the United States, have great influence over what is and is not considered to be a valid postage stamp.

For instance, in the 1960s the countries of the United Arab Emirates issued many stamps that were likely never actually on sale in a post office, so Scott does not list most of them.

To some extent, this is unavoidable, since the ban on importation means that Scott's editors are unable even to acquire copies of the stamps to be described.

Shortly after the program was announced, Scott Publishing received a letter from Hsien-ming Meng, a physician in Dayton, Ohio, and worldwide collector of mint stamps with a nearly complete collection.

Together with generous access by many other collectors, Meng's cooperation has resulted in creation of scanned images of all but about 1300 stamps by Scott as of 2024 catalogue series.

[2] Scott Publishing Co also produces a related volume which more comprehensively lists all United States Postage Stamps and Postal History.

It is generally known as the Scott Specialized and is regarded by many as the definitive single volume reference to USA postage stamps.