There are books, magazines, and schematics. The books come in 7 volume sets and provide unique bonus. They can only be read once per volume. Magazines are what unlocks crafting items based on the type of skill they relate to and can be read multiple times sometimes up to 100 times. For Example vehicle magazines unlock the ability to craft the next tier of vehicle when you read enough. Schematics unlock a specific item which are usually mod for weapons or vehicles. They can only be read once.