This is simply a form of paper. Since there are very few trees, most correspondence and most books are now created from pulp produced by the desert hemp plant. Desert hemp that has been leached, bleached, pulped, smashed, compressed, and dried is called Heffis. Heffis is very smooth and ages quite well. It is durable and its only drawback is its tendency to fall apart when exposed to water. Because of this it is possible to "dissolve" a Heffis book or letter by simply immersing it in water (although due to the cost of water, this would be somewhat of a waste and most people will simply burn Heffis to get rid of it).
Recent emergencies in the US may have you thinking about emergency preparedness. Get your survival gear ready for the next event.