Wars require the movement of troops and material, and this requires communication, which means mail. The hundreds of thousands of Americans who were sent to fight and die in France at the end of World War I were sent with two postal issues all of their own. Soldiers like booklet stamps as they can be carried in backpacks. The cardboard covers keep the stamps somewhat safe from damage, and such booklets are easier to store for when they are needed. And WW I was the war of the trenches. Between the senseless running toward machine guns for a few feet of gain which were called battles in that war were long periods of inactivity in the trenches. There is just so much time you can devote to playing cards, and these men had lots of time to write home. Ordinary booklets were used up too quickly, so the Post Office created booklets of thirty stamps of the one cent and the two cent values just for the soldiers of the American Expeditionary Force in France.Â
These booklets intact are scarce and the two cent in particular is a great rarity, cataloging for $25,000. Collectors can still make finds associated with this group though. The stamps of the booklet panes look identical to the eye to the regular 1c and 2c stamp but they were printed from specially prepared plates and the stamps are somewhat bigger. Singles can be found on cover in dealer 25c boxes with AEF cancellations overlooked as the rare items they are because the stamps look like the cheaper varieties) and these covers when properly certified are worth several hundred dollars each.