First day covers of stamps are examples of the simple straightforward cover collecting that the majority of casual collectors in this country partake of. It is a basic FDC with the cachet on the left tied into the theme of the stamp. Unaddressed, having never gone through the posts, it looks good in an album. Not having gone through the mail, except under another cover, it is not a piece of postal history, but a souvenir of the release of the stamp that franks it.
US History In Stamps and Cover Art
But in general cover collecting isn't that simple. In fact the weekend collector can still be found at stamp shows and in shops (virtual and otherwise) calling covers FDCs when they aren't. This isn’t a major crime of course, as the culprit in the confusion is usually the cachet.
Early illustrated covers were in the service of propaganda and politics, like campaign covers of the type Karl Rove collects. Patriotic Civil War covers, avidly collected today, also were wildly popular for use in correspondence during their era. Designs were not just boosters of Northern patriotism, but also anti-Southern propaganda.
The Golden Age of Stamps and Covers
After the Civil War and Reconstruction a rebounding US produced the next species in the evolution of covers that are prized today: advertising covers, which promoted a merchant's product or a tradesman's service via the mails. These remained in popular use into the 1950's. But in the meantime the world of collecting had taken a cue from this form of illustrated envelope art and began producing cachets for everything from airport dedications to ship christenings to bombings of enemies in WWII.
This is where things got confusing for the cover collector. One has to be aware of the commemorative nature of many of the covers produced in the so-called classic era of stamp collecting, roughly 1920-50. In his catalog Flag Cachet And Compendium Paul Abajian writes "The novice will often confuse the designs found on pre 1925 envelopes with cachets. Many of these patriotic designs reflecting national pride or promotional advertising designs are...highly collectible (but) do not meet the definition of a cachet as defined."
I would add that it is not just pre 1925, but also the era of WWII that holds pitfalls for the collector who may think he is paying a pittance for an early FDC, when in reality he is getting exactly what he paid for -- a cacheted envelope where the stamp has little or nothing to do with the design on the cover.
Stamps and Cover Catalogs End the Confusion
The hard core first day cover collector doesn't have such problems: there are a number of cachet catalogs to help avoid the confusion. Michael Mellone’s catalogs cover FDCs over many decades. And the bible for FDC collectors is the Planty Photo Encyclopedia of Cacheted First Day Covers, a multi-volume catalog that encompasses the world of FDC collecting.