Leather

Leather is an animal skin used to make armor and books.

Drops from animals
Cows, mooshrooms, horses, donkeys, mules and llamas drop 0-2 pieces of leather upon death.

Fishing
Leather can be obtained as a "junk" item from fishing.

Trading
Leatherworker villagers will buy 9–12 leather for one emerald.

Novice-level leatherworker villagers have a $2/3$ chance to buy 6 leather for one emerald in Java Edition, and will always offer the trade in Bedrock Edition.

Repairing
Leather armor can be repaired with leather in an anvil.

Issues
Kůže Leder Cuero Cuir Bőr Cuoio 革 가죽 Leer Skóra Couro Кожа 皮革