The word book comes from the latin liber, a term that is related to the bark of the tree. A book is an assemblage of sheets of paper or other similar material which, once connected, form a volume.
And after UNESCO, a book must have at least 50 pages. Otherwise, one is dealing to a brochure or a simple slip. It is noted, however, that there are digital books (e-books, which have no leaves but rather archives to read through a computer or any other electronic device specific), audio books (the registry from someone who reads to make the book accessible to blind people, for example) and audio books (text recorded on a tape in a box that has the appearance of a book).
In general, book means any literary, scientific or of another kind, work with the extension needed to form a volume: "The Colombian Nobel Prize comes to present his latest book," "my dream is to publish a book of poetry", "I always have a book on my bedside table.
The concept of book includes some meanings more specific or directly different from those mentioned above. Industry of printing (publishing) as well as the respective staff form the book. ("Before, the book was a more profitable than now branch").
In accounting, the book (or book-journal) is a register on which we note all operations in their chronological order.
Figuratively, it's about providing a source of education and knowledge.
Then, in the occult, the black book has to do with witchcraft or magic.