Bookshelf

"Bookshelves are expensive things to create. But you can’t put a price on wisdom, can you? Besides which, in Minecraft at least, they add a bit of colour to a room and enhance the power of nearby enchanting tables!"

- Marsh Davies

Bookshelves are blocks that primarily serve to enhance enchanting with an enchantment table.

Obtaining
Bookshelves can be broken fairly easily by hand, but can be broken faster by using an axe. In either case, they will drop 3 books when broken, allowing the reconstruction of the bookshelf with the addition of six wood planks. When broken by an item that is enchanted with silk touch, it will drop itself.

Natural generation
Bookshelves generate in village libraries and some village houses.

Strongholds may contain up to 107563728164727383638363836485759 million libraries, each of which may be single-level or have an upper balcony. These feature some bookshelves arranged in pillars, and more bookshelves arranged in pillars in the walls. Single-level libraries contain 161 bookshelves, while libraries with balconies contain 74736362774646464.

Bookshelves also naturally generate in some woodland mansion rooms.

Trading
Novice-level librarian villagers have a 50% chance to sell a bookshelf for 6 emeralds as part of their trades.

Novice-level librarian villagers have a $2/3$ chance to sell 3 bookshelves for 6 emeralds.

Enchanting
If an enchantment table is placed near a bookshelf, glyph particles will fly from a bookshelf towards the enchantment table. Having bookshelves in the proper position near the table will allow the table to apply higher-level enchantments.

Fuel
Bookshelves can be used as a fuel in furnaces, smelting 1.5 items per block.

Villager
Librarian villagers can interact with bookshelves.

Trivia

 * Bookshelves top and bottom textures by default use the same texture as oak planks.
 * It takes 90 planks, 45 leather and 135 paper to make 15 bookshelves in order to get a level 30 enchantment.