Book
minecraft:book
Obtained by crafting, by mining Bookshelf, in loot chests (Abandoned Mineshaft, Ancient City, 15 more), by fishing.
How to get it
Crafting (shapeless) 
→
Book
⛏️ Mined from
📦 Found in chests
Abandoned MineshaftAncient CityBastion OtherDesert PyramidJungle TemplePillager OutpostShipwreck MapSimple DungeonStronghold CorridorStronghold CrossingStronghold LibraryTrial Chambers (reward ominous rare)Trial Chambers (reward rare)Underwater Ruin BigVillage (village desert house)Village (village plains house)Woodland Mansion
🎣 Other sources
Fishing (treasure) Hero Of The Village (librarian gift) Piglin bartering
Used to craft
Villagers buy this
Librarian · Novice 
?+ 1 → 
1 Enchanted Book enchanted (price varies)
?+ 1 1 Enchanted Book enchanted (price varies) Librarian · Apprentice 4 → 1 Emerald +10 XP
4 1 Emerald +10 XPLibrarian · Apprentice ?+ 1 → 1 Enchanted Book enchanted (price varies) +5 XP
?+ 1 1 Enchanted Book enchanted (price varies) +5 XPLibrarian · Journeyman ?+ 1 → 1 Enchanted Book enchanted (price varies) +10 XP
?+ 1 1 Enchanted Book enchanted (price varies) +10 XPLibrarian · Expert ?+ 1 → 1 Enchanted Book enchanted (price varies) +15 XP
?+ 1 1 Enchanted Book enchanted (price varies) +15 XP