All transit books -- linking and descriptive -- are fragile, and will be destroyed if left alone.
Normal minecraft dropped objects are just passive items, that die after 5 minutes of time pass. Mystcraft books are actual entities, like minecarts, with the ability to respond to things happening to them and **CANNOT** be picked up by "bumping" into them like other items.
They do not like water. Not at all. Keep them dry, or the ink will run and the symbols will be useless. Such a book goes poof very fast.
Even when not exposed to water, they still die fairly quickly just exposed to air. They last about an hour before losing all durability and vanishing. Suffice to say, this is still a short time if you just leave them laying around.
A book can be safely protected in the world by * Placing it on a [[items:linkbook stand]] * Placing it on a [[items:lectern]] * Storing it inside other blocks, such as chests (including ender chests).
Remember: **If you use the book from your hotbar, it will be dropped on the floor behind you!** Hotbar linking is very useful for a cheap escape linking book, and is the best way to use that **emergency return home linking book that always stays on your hotbar no matter what**.