Stamp catalogs are large undertakings, since there are thousands of new stamps to describe each year.
In recent years, stamp catalogs have moved from print to online. Yet, in print or online, their purpose remains to provide graphics and text that help identify stamps from the past, present and near future.
But which, you may ask, is the most popular stamp catalog in the U.S.? Without doubt, it must be the Scott Catalog, first published in 1868 as a 21-page pamphlet. Nowadays it span five large volumes but the most up-to-date version is available online and sold via subscription. Visit www.scottonline.com for details. For stamp collectors worldwide, the Scott Catalog remains the authoritative source on stamp identification.
The print copy can still be found in most moderate to large-sized libraries. Volume One covers stamps from the United States, while the subsequent volumes covers other countries, listed in alphabetical order. A CD is also available in some libraries.
The Scott catalog wields a large influence in being an extensive source of stamp issues from the last 150 years. Its influence is such that most U.S. dealers will refuse to trade stamps that are not listed -- to some extent the Scott catalog defines what qualifies as a valid stamp, helping set the standards of quality.
In Europe, two catalogs are more influential: Michel and Stanley Gibbons. Michel which will soon celebrate its 100 anniversary since it was first published in 1910. The catalog is available online at www.michel.de. Though printed in German the Michel catalog is heavily used by American and other dealers and collectors. The graphics are still useful and the text is often simple enough that those with a knowledge of only a smattering of German can follow well enough for the catalog to be valuable.
Turn to UK for an even older catalog: the Stanley Gibbons catalog, first published in 1865. This British company rightly claims to having first developed the market for trading stamps in Britain. Their influence now ranges far outside the UK, however where they operate several businesses: the catalog, an online shop, online auctions and more. Visit them at www.stanleygibbons.com.
There are dozens of other large catalogs emanating from and covering other countries around the world - France (Yvert et Tellier, www.yvert.com), Sweden (Facit, www.facit.se), Switzerland (Zumstein, www.briefmarken.ch), Australia (Brusden-White, www.brusden-white.com.au) and others all enjoy their homegrown variety. And this is as is should be, since philately is both a hobby enjoyed and a business practiced all over the globe.
Postal administrations may also issue catalogs but they contain less details, since they are intended for children and less-experienced collectors.
The catalogs, and many other sources, are helpful to determine the value and validity of a stamp collection. But they also serve as a reference for dreaming about and pursuing those gems that a stamp collector seeks to acquire in the future.
Be warned that the prices listed are indicative only (when the publishers are not dealers, they collect data from dealers and auctions). Prices will vary according to local market condition. It is worthwhile to shop around as the price will vary from dealer to dealer and among stamp collectors.
Good reading! Good hunting!