There are four major worldwide international catalogs (plus several smaller single area specialized catalogs such as Facit for Scandinavia and Zumstein for Switzerland, which are only issued for their home countries and whose publishers have no worldwide versions of their catalogs). German philatelists collect their stamps by the Michel catalog, which publishes a worldwide catalog in German, along with a highly specialized catalog of Germany and area. Yvert is the French catalog which does substantially the same thing for francophones, again with a specialized France and Colonies catalog. Gibbons is published in Great Britain and once was a worldwide catalog, though their most popular yearly offering is a British Commonwealth catalog that is the standard for collecting the former British Colonies. And in America, we have the Scott catalog, published every year in numerous (costly) volumes. It is only a matter of time, perhaps even in less than a decade, when the last of the annual catalogs are published, and all catalogs and their updates will be found online. Each of the four major worldwide catalogs have their strengths and weaknesses.
Michel is the world’s most successful catalog in terms of printing profits and number of users. It helps that Michel is printed for the enormous German stamp market, but philately, at least the way most collectors collect today, is really a German invention. The Michel catalog has several unique factors about it that make it fun to use. First, the set up for perf varieties is far easier to use than Scott. Michel uses small letters after the number to designate varieties, as does Scott, but there is a consistency in the listing and layout that make cataloging perf and watermark varieties far easier to find in Michel than in any other catalog. Additionally, the Germans love their booklets and booklet panes and list, for nearly every country, extensive booklet and advertising combinations that no other catalog touches. There is a compelling logic about the Michel set up, and most worldwide philatelists who have had experience with all the major catalogs find it the easiest and most appealing to use. Of course, the Michel Germany and Area catalog is without peer, listing hundreds of thousands of varieties in a couple thousand pages and making even the most complex area of German philately approachable.
Yvert does not as good of a job. The worldwide catalog suffers from production delays