Enchanting books can be found in boxes generated in the world, purchased from librarians and villagers with emeralds, obtained with enchantment tables, and obtained by fishing after 1.7.
They can be used to add spells to items, including some items that cannot be enchanted through the enchantment table. This can be done on the anvil like a combined item, but the book replaces the position of the sacrificial item.
Using books to get the same spell requires much less experience than combining items. This is reasonable, because it takes experience to create enchanted books.
However, enchanted items require materials and experience, and it is possible to obtain multiple spells. Therefore, it is a waste of experience to use books as enchanted items, and this method will not repair items at the same time, but renaming is still possible.
Some enchantment books can give items some spells that are not available on the enchantment table (such as accurately collecting scissors and stabbing boots).
In the creation mode, the enchantment book can be used to enchant any object.