There is much more to postal history than just the stamps. The evolution of the cover, for example. Prior to the first International Postal Congress, there were no set rules on an envelope or postcard, anything went. Envelopes were generally home-made, in any size and shape imaginable, squares, rectangles, and folded into triangles. The stamps were placed wherever the sender felt like putting them. Postcards, even 'official' cards, published by a civil government, came in a multitude of sizes. The privately issued cards came in a variety of sizes, weights & material. Some were no bigger than a playing card, others as large as a  half sheet of paper. Some were made of wood or leather. Postcards made of silk are highly sought after by collectors.

The "well-to-do" & large companies used private post offices that issued their own stamps. Every country had its own rules governing how the mail was handled and which pieces were acceptable. With the advent of air mail, and more mail traveling internationally, standards had to be agreed upon. The 1st International Postal Congress established these rules.

Security cover w wax seal & block of six-egypt

We have tried to cover (pardon me for that) the postal gamut. Air Mail, Postage Due, Registered Mail, Parcel Post, Censored Mail, Damaged Mail, Resealed Mail, Fumigated Mail, Express, First Day of Issue, Postcards, Commercial and Domestic Mail, Postal Revenues & Tax stamps have all been... covered. (Sorry I did it again. I cant help it.) We also threw in a couple commemorative cancels, invoices and bills of sale just because we could.

Airmail to germany w multiple franking-argentina

Most of the actual postal references were taken from auctions on Ebay. Some were scanned from our own collection. (If you have any interest, and since you've read this far I assume you do.) It is well worth taking a look at the stuff on Ebay, even if you don't buy. The amount of reference material is mind boggling.

Domestic inflation cover-germany

There are still interesting areas that we didn't cover. (I cant' shut it off!) Souvenir Sheets, Memory Cards, Field post (Military Mail), Catapult Mail, Sea-borne Mail, Rocket Mail, Zeppelin Mail, blocks of four and strips, Cinderella's & tin can mail are just a few that come to mind.

Zepplin cover first round trip flight-graf zepplin-germany/buenos aires/chicago w commemorative strike-germany

First pan-american round trip flight-graf zepplin w
2 commemorative strikes-germany

Commercial stampless cover w american/british
censors-afganistan to new york

Registered inflation cover-argentina

Zeppelin condor cachet cover-argentina to germany- w special strike

Commercial, international, registered air mail cover- Russia to USA

First flight cachet cover-brussels to hanover w/ special strike

'Tin can' mail cover-transport by canoe-fiji

German inflation cover-1500 marks

Special event commercial cover

Zeppelin mail cover-graf zeppelin-w 2 specialstrikes