Most if the threads about dwarven books and writing suggests that they use paper or parchment as a base material. I propose a more original, more dwarven, more awesome method: etched metal plates.
Etching creates patterns on metal via application of acid, and will be done in-game at an "Etcher's desk", or perhaps a normal table. Books will consist of several metal plates bound together. Along with skill at reading, there will be a separate skill in etching, determining how fast the etcher works and the quality of the writing (similar to Nethack's engraving system).
Etching will be an essential skill for bookkeepers and doctors. The bookkeeper records down stockpile and population figures in a records book annually, as well as significant events like sieges, births, deaths and the arrival of uninvited guests. The player needs the records book to view stockpile figures, and will also be able to view the figures and events of previous years in the book. The doctor records down medical histories of the dwarves he treats in a medical log. Without the log, the medical histories cannot be viewed.
Books are commissioned by the player. A new book is commissioned with a name, number of plates and a function(records book, medical log, custom). A records book and medical log will be part of the starting embark by default. New plates can be added to existing books. In custom books, players may make their own entries, a feature useful for succession games and shared fortresses. Books can be viewed in a separate menu similar to the artifacts screen.
Finally, books are stored in a room designated from a bookshelf as a "library". Bookshelves in the room will be used to store books, the same way dwarves store owned items in coffers.