We know what philately is. And we have a grasp of what the term cover means. But what about philatelic covers? Covers can be categorized as one of two general types: postal history, which are items that have actually traveled through the mail system; and philatelic covers, the covers that are produced or made specifically with elements that appeal to a collector. The most well known type of a philatelic cover is the first day cover (FDC), a stamp souvenir, collected unaddressed and never intended to go through the mails.
1. Topical Covers
Collecting covers from the 1939 Worlds Fair in New York is a great area, as all fair related items are enthusiastically collected. Aside from the large variety of FDCs that were issued for the US stamp honoring the fair, there were numerous event covers, with cachets honoring everything from hula dancers to the visits of British Royalty. Of course virtually any cover can be a topical cover as long as it has an element that allows it to fit into your topical collection. But like FDCs these covers are considered by postal historians to be contrived and not legitimized by having as their primary purpose a journey through the mails.
2. Flight Covers
First flight covers represent the history of flight, as they were carried in aircraft on the first flight establishing a new air mail route. They are considered contrived by some, although others think the fact that they have traveled through the mail system -- by air -- qualifies them as postal history. But the jury's still out. Still, covers from pioneering flights by the likes of Lindbergh, Wiley Post and Amelia Earhart are souvenir collectibles that get the air mail cover collector’s adrenaline flowing. It doesn't matter to these collectors if someone may not approve of these items for whatever reason.
3. Pictorial and Slogan Cancel CoversPictorial cancels can be anything from aircraft to commemorate an air mail club stamp show to an orchid cancel for the local flower show. They are mostly commemorative in nature. Slogan cancels can be commemorative to note the centenary of a college or institution, or the anniversary of an historic battle, etc. But more often than not they are promotional, alerting one to upcoming events like national stamp collecting month and the like. With our mails now using meter franking more than stamps, these are far less plentiful than they once were.
4. Stamp Dealer CoversStamp dealer covers, although not as widely collected as other types of philatelic cover, are collected by those who enjoy the history of philately itself. These have seen postal use, but are often fashioned to please collectors, not the postal authorities. Like all philatelic covers they are held in lower regard by true postal historians, to whom proper rate usage of stamps is so important. Dealer covers are serendipitous byproducts of stamp collecting -- and sought after thanks to their sometimes striking illustrations of stamps and related material, as well as interesting franking using out of date and collectible stamps.
5. Mail Art Covers
There is a thriving underground of mail artists who use stamps and covers in imaginative and unusual ways. Often thought of as merely fun kid’s stuff, with envelopes festooned with stickers and the like, there is, in reality, a whole network of artists who express themselves through the mails. These artists and their work have been gaining in influence since brought to national attention in the U.S. by the likes of Ray Johnson and the Fluxus movement in the 60s. With the increase in popularity in artists' cachets for FDCs in the philatelic world, the ranks of FDC dealers has been added to by mail artists who enjoy plying their trade in the interest of the stamp and cover collector.