Crafting Recipe
6 planks (top+bottom rows) + 3 books (middle row) = 1 bookshelf. 15 bookshelves around an enchanting table enable level-30 enchants. Also excellent for decorating libraries and studies.
Enchanting Core
Bookshelves are the only way to raise enchanting levels: place 15 within one block of the table (three tiers, at or one above table height) to unlock level-30 enchantments. The gap between shelf and table must stay empty — no torches, no snow.
Other Uses
Bookshelves craft lecterns (for villager professions) and are central to libraries and studies. Each takes 6 planks and 3 books; books need leather (cows) and sugar cane (paper), so pair them with livestock and cane farms.