diff --git a/SDK/CRT/INC/stddef.h b/SDK/INC/CRT/stddef.h
similarity index 100%
rename from SDK/CRT/INC/stddef.h
rename to SDK/INC/CRT/stddef.h
diff --git a/SDK/CRT/INC/string.h b/SDK/INC/CRT/string.h
similarity index 100%
rename from SDK/CRT/INC/string.h
rename to SDK/INC/CRT/string.h
diff --git a/SDK/CRT/INC/wchar.h b/SDK/INC/CRT/wchar.h
similarity index 100%
rename from SDK/CRT/INC/wchar.h
rename to SDK/INC/CRT/wchar.h
diff --git a/BOOT/ENVIRON/INC/nt.h b/SDK/INC/NT/nt.h
similarity index 92%
rename from BOOT/ENVIRON/INC/nt.h
rename to SDK/INC/NT/nt.h
index 123ac4a..fbdd8e4 100644
--- a/BOOT/ENVIRON/INC/nt.h
+++ b/SDK/INC/NT/nt.h
@@ -20,4 +20,4 @@ Abstract:
 #include <ntstatus.h>
 #include <ntimage.h>
 
-#endif
+#endif /* !_NT_H */
diff --git a/BOOT/ENVIRON/INC/ntdef.h b/SDK/INC/NT/ntdef.h
similarity index 74%
rename from BOOT/ENVIRON/INC/ntdef.h
rename to SDK/INC/NT/ntdef.h
index 0c593d7..d0d1abe 100644
--- a/BOOT/ENVIRON/INC/ntdef.h
+++ b/SDK/INC/NT/ntdef.h
@@ -16,42 +16,55 @@ Abstract:
 #ifndef _NTDEF_H
 #define _NTDEF_H
 
+#include <string.h>
+
+#ifndef IN
+#define IN
+#endif
+
+#ifndef OUT
+#define OUT
+#endif
+
+#ifndef OPTIONAL
+#define OPTIONAL
+#endif
+
+#ifndef FASTCALL
+#define FASTCALL
+#endif
+
+#ifndef NTAPI
+#define NTAPI
+#endif
+
 #ifndef VOID
-    #define VOID void
+#define VOID void
 #endif
 
 #ifndef CONST
-    #define CONST const
-#endif
-
-#ifndef IN
-    #define IN
-    #define OUT
-    #define OPTIONAL
+#define CONST const
 #endif
 
 #ifndef ANYSIZE_ARRAY
-    #define ANYSIZE_ARRAY 1
+#define ANYSIZE_ARRAY 1
 #endif
 
 #ifndef FORCEINLINE
 #if defined(_MSC_EXTENSIONS)
-    #define FORCEINLINE __inline
+#define FORCEINLINE __inline
 #else
-    #define FORCEINLINE static inline
+#define FORCEINLINE static inline
 #endif
 #endif
 
-#ifndef FASTCALL
-    #define FASTCALL
-#endif
-
-#ifndef NTAPI
-    #define NTAPI
-#endif
-
-#undef NULL
+#ifndef NULL
+#ifdef __cplusplus
+#define NULL 0
+#else
 #define NULL ((VOID *)0)
+#endif
+#endif
 
 //
 // Basic types.
@@ -64,9 +77,9 @@ typedef unsigned short USHORT;
 typedef unsigned long ULONG;
 
 //
-// Basic type pointers.
+// Basic pointer types.
 //
-typedef void *PVOID;
+typedef VOID *PVOID;
 typedef CHAR *PCHAR;
 typedef SHORT *PSHORT;
 typedef UCHAR *PUCHAR;
@@ -74,17 +87,24 @@ typedef USHORT *PUSHORT;
 typedef ULONG *PULONG;
 
 //
-// Wide characters.
-//
-typedef USHORT WCHAR;
-typedef WCHAR *PWCHAR;
-
-//
-// Logical values.
+// Logical value types.
 //
 typedef ULONG LOGICAL;
 typedef ULONG *PLOGICAL;
 
+//
+// String types.
+//
+typedef CHAR *LPSTR;
+typedef CONST CHAR *LPCSTR;
+
+//
+// Wide character/string types.
+//
+typedef USHORT WCHAR;
+typedef WCHAR *PWCHAR, *LPWSTR;
+typedef CONST WCHAR *LPCWSTR;
+
 //
 // Status codes.
 //
@@ -103,14 +123,14 @@ typedef NTSTATUS *PNTSTATUS;
 // Long long type definitions.
 //
 #if defined(_MSC_EXTENSIONS)
-    typedef unsigned __int64 ULONGLONG;
-    typedef __int64 LONGLONG;
+typedef unsigned __int64 ULONGLONG;
+typedef __int64 LONGLONG;
 #elif defined(UNIX_LP64)
-    typedef unsigned long ULONGLONG;
-    typedef long LONGLONG;
+typedef unsigned long ULONGLONG;
+typedef long LONGLONG;
 #else
-    typedef unsigned long long ULONGLONG;
-    typedef long long LONGLONG;
+typedef unsigned long long ULONGLONG;
+typedef long long LONGLONG;
 #endif
 
 //
@@ -160,21 +180,4 @@ typedef struct _LIST_ENTRY {
     struct _LIST_ENTRY *BackLink;
 } LIST_ENTRY, *PLIST_ENTRY;
 
-//
-// Runtime library definitions.
-//
-
-PVOID
-RtlCopyMemory (
-    PVOID Destination,
-    CONST PVOID Source,
-    ULONG Length
-    );
-
-PVOID
-RtlZeroMemory (
-    PVOID Destination,
-    ULONG Length
-    );
-
-#endif
+#endif /* !_NTDEF_H */
diff --git a/BOOT/ENVIRON/INC/ntimage.h b/SDK/INC/NT/ntimage.h
similarity index 93%
rename from BOOT/ENVIRON/INC/ntimage.h
rename to SDK/INC/NT/ntimage.h
index b983514..6100e0e 100644
--- a/BOOT/ENVIRON/INC/ntimage.h
+++ b/SDK/INC/NT/ntimage.h
@@ -23,4 +23,4 @@ Abstract:
 #define IMAGE_FILE_MACHINE_I386    0x014c
 #define IMAGE_FILE_MACHINE_AMD64   0x8664
 
-#endif
+#endif /* !_NTIMAGE_H */
diff --git a/SDK/INC/NT/ntrtl.h b/SDK/INC/NT/ntrtl.h
new file mode 100644
index 0000000..4e9f5ed
--- /dev/null
+++ b/SDK/INC/NT/ntrtl.h
@@ -0,0 +1,29 @@
+/*++
+
+Copyright (c) 2024, Quinn Stephens.
+Provided under the BSD 3-Clause license.
+
+Module Name:
+
+   ntrtl.h
+
+Abstract:
+
+   Provides NT RTL (Run-Time Library) definitions.
+
+--*/
+
+#ifndef _NTRTL_H
+#define _NTRTL_H
+
+#include <string.h>
+
+//
+// Memory operations.
+//
+#define RtlMoveMemory(Destination, Source, Length) memmove((Destination), (Source), (Length))
+#define RtlCopyMemory(Destination, Source, Length) memcpy((Destination), (Source), (Length))
+#define RtlFillMemory(Destination, Length, Fill)   memset((Destination), (Fill), (Length))
+#define RtlZeroMemory(Destination, Length)         memset((Destination), 0, (Length))
+
+#endif /* !_NTRTL_H */
diff --git a/BOOT/ENVIRON/INC/ntstatus.h b/SDK/INC/NT/ntstatus.h
similarity index 98%
rename from BOOT/ENVIRON/INC/ntstatus.h
rename to SDK/INC/NT/ntstatus.h
index b490fad..3603078 100644
--- a/BOOT/ENVIRON/INC/ntstatus.h
+++ b/SDK/INC/NT/ntstatus.h
@@ -41,4 +41,4 @@ Abstract:
 #define STATUS_DRIVER_UNABLE_TO_LOAD   ((NTSTATUS) 0xC000026CL)
 #define STATUS_NO_MATCH                ((NTSTATUS) 0xC0000272L)
 
-#endif
+#endif /* !_NTSTATUS_H */
diff --git a/premake5.lua b/premake5.lua
index f75122c..3e53787 100644
--- a/premake5.lua
+++ b/premake5.lua
@@ -25,11 +25,11 @@ project("CRT")
     kind("StaticLib")
     location("SDK/CRT")
 
-    includedirs({ "SDK/CRT/INC" })
+    includedirs({ "SDK/INC/CRT" })
     objdir("BUILD/SDK/CRT")
     targetdir("BUILD/SDK")
     targetname("crt")
-    files({ "SDK/CRT/INC/**.h", "SDK/CRT/**.c" })
+    files({ "SDK/INC/CRT/**.h", "SDK/CRT/**.c" })
 
 --[[
 project("BOOT")