diff --git a/src/main/java/emu/grasscutter/game/player/PlayerCodex.java b/src/main/java/emu/grasscutter/game/player/PlayerCodex.java
index bb17a3e4..0a6e8265 100644
--- a/src/main/java/emu/grasscutter/game/player/PlayerCodex.java
+++ b/src/main/java/emu/grasscutter/game/player/PlayerCodex.java
@@ -119,4 +119,10 @@ public class PlayerCodex {
         this.player.save();
         this.player.sendPacket(new PacketCodexDataUpdateNotify(7, viewpoint.getId()));
     }
+
+    public void checkBook(int bookId) {
+        this.getUnlockedBook().add(bookId);
+        this.player.save();
+        this.player.sendPacket(new PacketCodexDataUpdateNotify(5, bookId));
+    }
 }
diff --git a/src/main/java/emu/grasscutter/game/props/ItemUseAction/ItemUseAction.java b/src/main/java/emu/grasscutter/game/props/ItemUseAction/ItemUseAction.java
index 6af7ac8e..1ee53b82 100644
--- a/src/main/java/emu/grasscutter/game/props/ItemUseAction/ItemUseAction.java
+++ b/src/main/java/emu/grasscutter/game/props/ItemUseAction/ItemUseAction.java
@@ -38,7 +38,7 @@ public class ItemUseAction {
             case ITEM_USE_MAKE_GADGET -> new ItemUseMakeGadget(useParam);
             // Unlock recipes - TODO: allow scheduling packets for after recipe is removed
             case ITEM_USE_UNLOCK_COMBINE -> new ItemUseUnlockCombine(useParam);
-            case ITEM_USE_UNLOCK_CODEX -> new ItemUseUnlockCodex(useParam);  // TODO: No backend for this yet
+            case ITEM_USE_UNLOCK_CODEX -> new ItemUseUnlockCodex(useParam);
             case ITEM_USE_UNLOCK_COOK_RECIPE -> new ItemUseUnlockCookRecipe(useParam);
             case ITEM_USE_UNLOCK_FORGE -> new ItemUseUnlockForge(useParam);
             case ITEM_USE_UNLOCK_FURNITURE_FORMULA -> new ItemUseUnlockFurnitureFormula(useParam);
diff --git a/src/main/java/emu/grasscutter/game/props/ItemUseAction/ItemUseUnlockCodex.java b/src/main/java/emu/grasscutter/game/props/ItemUseAction/ItemUseUnlockCodex.java
index 0d62e770..bd80867e 100644
--- a/src/main/java/emu/grasscutter/game/props/ItemUseAction/ItemUseUnlockCodex.java
+++ b/src/main/java/emu/grasscutter/game/props/ItemUseAction/ItemUseUnlockCodex.java
@@ -1,6 +1,7 @@
 package emu.grasscutter.game.props.ItemUseAction;
 
 import emu.grasscutter.game.props.ItemUseOp;
+import emu.grasscutter.server.packet.send.PacketCodexDataUpdateNotify;
 
 public class ItemUseUnlockCodex extends ItemUseInt {
     @Override
@@ -14,6 +15,7 @@ public class ItemUseUnlockCodex extends ItemUseInt {
 
     @Override
     public boolean useItem(UseItemParams params) {
-        return false;
+        params.player.getCodex().checkBook(this.i);
+        return true;
     }
 }
diff --git a/src/main/java/emu/grasscutter/server/packet/send/PacketCodexDataFullNotify.java b/src/main/java/emu/grasscutter/server/packet/send/PacketCodexDataFullNotify.java
index 23d70d92..dd30c808 100644
--- a/src/main/java/emu/grasscutter/server/packet/send/PacketCodexDataFullNotify.java
+++ b/src/main/java/emu/grasscutter/server/packet/send/PacketCodexDataFullNotify.java
@@ -45,6 +45,7 @@ public class PacketCodexDataFullNotify extends BasePacket {
         CodexTypeData.Builder reliquaryData = CodexTypeData.newBuilder()
                 .setTypeValue(8);
 
+        //Quests
         player.getQuestManager().forEachMainQuest(mainQuest -> {
             if(mainQuest.isFinished()){
                 var codexQuest = GameData.getCodexQuestDataIdMap().get(mainQuest.getParentQuestId());
@@ -54,6 +55,7 @@ public class PacketCodexDataFullNotify extends BasePacket {
             }
         });
 
+        //Weapons
         player.getCodex().getUnlockedWeapon().forEach(weapon -> {
             var codexWeapon = GameData.getCodexWeaponDataIdMap().get(weapon);
             if(codexWeapon != null){
@@ -61,6 +63,7 @@ public class PacketCodexDataFullNotify extends BasePacket {
             }
         });
 
+        //Animals
         player.getCodex().getUnlockedAnimal().forEach((animal, amount) -> {
             var codexAnimal = GameData.getCodexAnimalDataMap().get(animal);
             if(codexAnimal != null){
@@ -68,19 +71,28 @@ public class PacketCodexDataFullNotify extends BasePacket {
             }
         });
 
+        //Materials
         player.getCodex().getUnlockedMaterial().forEach(material -> {
             var codexMaterial = GameData.getCodexMaterialDataIdMap().get(material);
-            if(codexMaterial != null){
+            if (codexMaterial != null) {
                 materialTypeData.addCodexIdList(codexMaterial.getId()).addAllHaveViewedList(Collections.singleton(true));
             }
         });
 
+        //Books
+        player.getCodex().getUnlockedBook().forEach(view -> bookTypeData.addCodexIdList(view).addAllHaveViewedList(Collections.singleton(true)));
+
+        //Tips
+        //TODO: Tips
+
+        //Views
+        player.getCodex().getUnlockedView().forEach(view -> viewTypeData.addCodexIdList(view).addAllHaveViewedList(Collections.singleton(true)));
+
+        //Reliquary
         player.getCodex().getUnlockedReliquarySuitCodex().forEach(reliquarySuit -> {
             reliquaryData.addCodexIdList(reliquarySuit).addAllHaveViewedList(Collections.singleton(true));
         });
 
-        player.getCodex().getUnlockedView().forEach(view -> viewTypeData.addCodexIdList(view).addAllHaveViewedList(Collections.singleton(true)));
-
         CodexDataFullNotify.Builder proto = CodexDataFullNotify.newBuilder()
                 .addTypeDataList(questTypeData.build())
                 .addTypeDataList(weaponTypeData)