Book and Quill

Books and quills are items used to turn books into written books. When a player signs a book, the book may not be edited in any way whatsoever. However some modifications may be implemented to the game allowing the player to get a plain signed book signed by no one.

Writing
By pressing the use key (right click by default) while holding a book and quill in their hand, the player can open a text editor GUI.

Using this GUI, the player can write a single book up to 50 pages long, with up to 256 characters per page (Note that line breaks, such as those created by pressing, are counted as two characters). No page may be longer than 13 lines and each line can have, on average, 19 characters. (The amount of characters possible per line is determined by the width of the used characters, which varies) In Singleplayer, the world will pause while a book is being edited. The player has the ability to copy and paste into books. However, the paste will fail if the text being pasted is longer than a single page. Mac users should also note that pasting only works by typing +, and that  +  has no effect.

Note that you cannot yet move the cursor while writing into a book, so it's currently impossible to go back and fix a typo without deleting what you've written after it. Selecting text is also unavailable.

When signed, a book will have the name of the player who wrote it, or "Player" if signed while playing offline. The title of the book can be up to 16 characters long, and the player cannot paste into a title. Special characters can be used in the title, if typed from a keyboard which has them. Alt codes do not work, and the § character cannot be typed even using a keyboard which has it implemented, meaning titles cannot be colored or formatted in-game. However, using 3rd-party programs to insert the § character, you can create colors and other formatting.

Special codes (coloring)
Text in a book can be styled using codes starting with the character (section sign), which may be copied and pasted into the book. In Windows, you can type it in a text editor by holding and typing 0167 or holding  and typing 21 on your numberpad. It can also be typed using +  +  on the US International keyboard,  +  on the Canadian Multilingual Standard keyboard,  +  on all German (QWERTZ) keyboard layouts, + on Mac,  +  +  for Linux systems with a key mapped to, or varying other shortcuts depending on locale and operating system.
 * + creates randomly changing characters.
 * + creates bold text.
 * + creates text with a strikethrough.
 * + creates underlined text.
 * + creates italic text.
 * + –  (hexadecimal) creates colored text. See Formatting Codes.
 * + resets any of the previous styles so text after it appears normally.

To use multiple formatting codes, the color code must be used first: it will cancel out all preceding codes. If you use multiple codes, and continue typing past the end of a line, the next line will exhibit only the last formatting code used.

Most Unicode characters are available in books, and although Windows alt-codes do not work, they may be pasted in without issue. One notable use of Unicode is fullwidth and small caps characters: in Minecraft, these appear as a different font altogether, which can be useful for titles or chapter headings. Converters exist which can take normal text and output fullwidth text, which can serve as a large convenience for those wishing to use it. Note that the font used in books is packaged with Minecraft itself, meaning a user's installed fonts do not affect which Unicode characters can be used or how they appear.

Trivia

 * In order to make the § symbol on Windows, hold down and press  on your number pad (far right side). On Mac OS X, press Option+6. On Linux, with the Compose key enabled, press  +  + . Note, however, that you cannot do this in-game, so you must copy the character and paste it into the game. On azerty keyboards, one can just press  and.
 * Other keyboards may also use instead of  and 21.
 * Even if your keyboard has a § key, you will need to copy and paste it.
 * Various in-game restrictions on books are not hard limits. Third party editors can make books have more than 50 pages, more than 256 characters per page, change author names, and have colored titles, among other things. These books will then function properly in vanilla Minecraft, meaning you may encounter such books on adventure maps or multiplayer servers.
 * Although the name blank is only 16 characters long, you can give it a longer name using an anvil.
 * If you rename a book and quill in an anvil before signing it, it will keep the name from the anvil instead of taking the name from signing.
 * If you rename a book and quill in an anvil before writing in it, you will not be capable of writing anything in the book. If something is written in it before it is renamed, then it will function normally.