An enchanted book does nothing on its own. It is a container: the enchantment lives inside it until you move it onto a real item with an anvil. That is the step most people miss, and it is why a chest full of books never seems to make your gear any better.
The short version
- Place an anvil and open it.
- Put the item you want to improve in the left slot.
- Put the enchanted book in the middle slot.
- Take the finished item from the right slot and pay the XP cost shown.
Order matters. Item on the left, book in the middle. Reversed, you will either get nothing or waste the book.
Why it sometimes says Too Expensive
Every trip through an anvil adds a hidden prior work penalty to the item, and that penalty doubles each time: 1, then 3, then 7, then 15, then 31 levels before the enchantment itself is even priced. Once a single operation would cost 40 levels or more, survival mode simply refuses.
The fix is to stop applying books one at a time. Combine the books with each other first, pairing cheap ones together, then put the single finished book onto your gear at the very end. The same set of enchantments often costs a third of what it would have done applied one by one.
Our Minecraft enchantment calculator works out that order for you and shows the XP cost at every step, flagging anything that would cross the 39-level ceiling.
Books that will not apply
If the anvil shows no result, one of three things is true. The enchantment does not work on that item type — Fortune will not go on a sword. It conflicts with something already there, like Silk Touch against Fortune or Mending against Infinity. Or the item is already at that enchantment’s maximum level.
Two books of the same enchantment at the same level combine into one book a level higher, up to the cap. Two Sharpness IV books make a Sharpness V book, which is how you reach the top levels without gambling at the table.
Where to get them
Librarian villagers are the reliable source: lock in a trade for the book you want and farm emeralds. Fishing with a Luck of the Sea rod pulls them up occasionally, and loot chests in temples, mineshafts, strongholds and ancient cities all carry them. Treasure enchantments like Mending never appear at an enchanting table at all, so trading or looting is the only route.
Full details on every enchantment, what it conflicts with and where it comes from are in the Minecraft enchantment list.