Because Karst paper is made from stone(yes, stone) and without cutting, transporting, or pulping trees, they save on energy and thousands of gallons of water usage, making Karst paper's carbon footprint 60% smaller for the same amount of wood-pulp paper. They're completely waterproof and tear resistant too and are heavier than most notebooks giving it a nice sturdy feel. That doesn't detract from the writing experience though. Each notebook contains 144 pages of A5 144gsm paper, an elasticated band, a page marker ribbon and a pocket attached to the back cover.