diff --git a/CMakeLists.txt b/CMakeLists.txt
index facab5a7..6cf311d2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -240,6 +240,35 @@ ${PROJECT_SOURCE_DIR}/dDatabase/*.cpp
 ${PROJECT_SOURCE_DIR}/dDatabase/Tables/*.cpp
 )
 
+file(
+    GLOB HEADERS_DDATABASE
+    LIST_DIRECTORIES false
+    ${PROJECT_SOURCE_DIR}/dDatabase/*.h
+    ${PROJECT_SOURCE_DIR}/dDatabase/Tables/*.h
+    ${PROJECT_SOURCE_DIR}/thirdparty/SQLite/*.h
+)
+
+file(
+    GLOB HEADERS_DZONEMANAGER
+    LIST_DIRECTORIES false
+    ${PROJECT_SOURCE_DIR}/dZoneManager/*.h
+)
+
+file(
+    GLOB HEADERS_DCOMMON
+    LIST_DIRECTORIES false
+    ${PROJECT_SOURCE_DIR}/dCommon/*.h
+)
+
+file(
+    GLOB HEADERS_DGAME
+    LIST_DIRECTORIES false
+    ${PROJECT_SOURCE_DIR}/dGame/Entity.h 
+    ${PROJECT_SOURCE_DIR}/dGame/dGameMessages/GameMessages.h
+    ${PROJECT_SOURCE_DIR}/dGame/EntityManager.h
+    ${PROJECT_SOURCE_DIR}/dScripts/CppScripts.h
+)
+
 # Source Code for dNet
 file(
 GLOB SOURCES_DNET
@@ -312,6 +341,33 @@ add_executable(AuthServer ${SOURCES_AUTH})
 add_executable(MasterServer ${SOURCES_MASTER})
 add_executable(ChatServer ${SOURCES_CHAT})
 
+# Add out precompiled headers
+target_precompile_headers(
+    dGame PRIVATE 
+    ${HEADERS_DGAME}
+)
+
+target_precompile_headers(
+    dZoneManager PRIVATE 
+    ${HEADERS_DZONEMANAGER}
+)
+
+# Need to specify to use the CXX compiler language here or else we get errors including <string>.
+target_precompile_headers(
+    dDatabase PRIVATE 
+    "$<$<COMPILE_LANGUAGE:CXX>:${HEADERS_DDATABASE}>"
+)
+
+target_precompile_headers(
+    dCommon PRIVATE
+    ${HEADERS_DCOMMON}
+)
+
+target_precompile_headers(
+    tinyxml2 PRIVATE
+    "$<$<COMPILE_LANGUAGE:CXX>:${PROJECT_SOURCE_DIR}/thirdparty/tinyxml2/tinyxml2.h>"
+)
+
 # Target libraries to link to:
 target_link_libraries(WorldServer dCommon)
 target_link_libraries(WorldServer dChatFilter)
diff --git a/dGame/dBehaviors/BehaviorSlot.h b/dGame/dBehaviors/BehaviorSlot.h
index 54ba5708..af0d4e03 100644
--- a/dGame/dBehaviors/BehaviorSlot.h
+++ b/dGame/dBehaviors/BehaviorSlot.h
@@ -1,5 +1,8 @@
 #pragma once
 
+#ifndef BEHAVIORSLOT_H
+#define BEHAVIORSLOT_H
+
 enum class BehaviorSlot
 {
 	Invalid = -1,
@@ -9,3 +12,5 @@ enum class BehaviorSlot
 	Head,
 	Consumable
 };
+
+#endif
diff --git a/dGame/dComponents/InventoryComponent.h b/dGame/dComponents/InventoryComponent.h
index bf18d132..1fda5942 100644
--- a/dGame/dComponents/InventoryComponent.h
+++ b/dGame/dComponents/InventoryComponent.h
@@ -1,5 +1,8 @@
 #pragma once
 
+#ifndef INVENTORYCOMPONENT_H
+#define INVENTORYCOMPONENT_H
+
 #include <map>
 #include <stack>
 
@@ -445,3 +448,5 @@ private:
      */
 	void UpdatePetXml(tinyxml2::XMLDocument* document);
 };
+
+#endif
diff --git a/dGame/dGameMessages/PropertySelectQueryProperty.h b/dGame/dGameMessages/PropertySelectQueryProperty.h
index 61fa7b86..e633f41b 100644
--- a/dGame/dGameMessages/PropertySelectQueryProperty.h
+++ b/dGame/dGameMessages/PropertySelectQueryProperty.h
@@ -1,5 +1,8 @@
 #pragma once
 
+#ifndef PROPERTYSELECTQUERY_H
+#define PROPERTYSELECTQUERY_H
+
 #include "Entity.h"
 
 class PropertySelectQueryProperty final
@@ -24,3 +27,5 @@ public:
     float PerformanceCost = 0;                      // The performance cost of the property
     uint32_t PerformanceIndex = 0;                  // The performance index of the property?  Always 0?
 };
+
+#endif
diff --git a/dGame/dInventory/Inventory.h b/dGame/dInventory/Inventory.h
index 0d3d9e69..b65a2040 100644
--- a/dGame/dInventory/Inventory.h
+++ b/dGame/dInventory/Inventory.h
@@ -1,5 +1,8 @@
 #pragma once
 
+#ifndef INVENTORY_H
+#define INVENTORY_H
+
 #include <map>
 #include <vector>
 
@@ -182,3 +185,5 @@ private:
      */
 	static std::vector<LOT> m_GameMasterRestrictedItems;
 };
+
+#endif
diff --git a/dGame/dMission/Mission.h b/dGame/dMission/Mission.h
index cca72daf..4fb6c60f 100644
--- a/dGame/dMission/Mission.h
+++ b/dGame/dMission/Mission.h
@@ -1,5 +1,8 @@
 #pragma once
 
+#ifndef MISSION_H
+#define MISSION_H
+
 #include <vector>
 #include <string>
 
@@ -259,3 +262,5 @@ private:
      */
 	std::vector<MissionTask*> m_Tasks;
 };
+
+#endif
diff --git a/dGame/dMission/MissionLockState.h b/dGame/dMission/MissionLockState.h
index 417c066a..e2dcedd7 100644
--- a/dGame/dMission/MissionLockState.h
+++ b/dGame/dMission/MissionLockState.h
@@ -1,8 +1,13 @@
 #pragma once
 
+#ifndef MISSIONLOCKSTATE_H
+#define MISSIONLOCKSTATE_H
+
 enum class MissionLockState : int
 {
 	MISSION_LOCK_LOCKED,
 	MISSION_LOCK_NEW,
 	MISSION_LOCK_UNLOCKED,
 };
+
+#endif
diff --git a/dGame/dMission/MissionTask.h b/dGame/dMission/MissionTask.h
index b77b9c59..3fcbbe3d 100644
--- a/dGame/dMission/MissionTask.h
+++ b/dGame/dMission/MissionTask.h
@@ -1,5 +1,8 @@
 #pragma once
 
+#ifndef MISSIONTASK_H
+#define MISSIONTASK_H
+
 #include "CDMissionTasksTable.h"
 #include "MissionTaskType.h"
 #include "dCommonVars.h"
@@ -180,3 +183,5 @@ private:
      */
 	void CheckCompletion() const;
 };
+
+#endif 
diff --git a/dGame/dMission/MissionTaskType.h b/dGame/dMission/MissionTaskType.h
index 263bf470..345f8fff 100644
--- a/dGame/dMission/MissionTaskType.h
+++ b/dGame/dMission/MissionTaskType.h
@@ -1,5 +1,8 @@
 #pragma once
 
+#ifndef MISSIONTASKTYPE_H
+#define MISSIONTASKTYPE_H
+
 //! An enum for mission task types
 enum class MissionTaskType : int {
     MISSION_TASK_TYPE_UNKNOWN = -1,                     //!< The task type is unknown
@@ -24,3 +27,5 @@ enum class MissionTaskType : int {
     MISSION_TASK_TYPE_PLACE_MODEL = 25,                //!< A task for picking up a model
     MISSION_TASK_TYPE_VISIT_PROPERTY = 30               //!< A task for visiting a property
 };
+
+#endif
diff --git a/dPhysics/dpCollisionGroups.h b/dPhysics/dpCollisionGroups.h
index 7a6830eb..5853070f 100644
--- a/dPhysics/dpCollisionGroups.h
+++ b/dPhysics/dpCollisionGroups.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#include <cstdint>
+
 /*
  * Collision Groups
  */