diff --git a/APIs.md b/APIs.md
index 43736c4..edb83a5 100644
--- a/APIs.md
+++ b/APIs.md
@@ -20,7 +20,7 @@ This is a complex API library written by Apple circa 1985. It consists of:
 
 Entry point is fixed at $4000 AUX, called MLI-style (JSR followed by command type and address of param block).
 
-See [MGTK.md](MGTK.md) for further documentation.
+See [MGTK.md](mgtk/MGTK.md) for further documentation.
 
 <!-- ============================================================ -->
 
diff --git a/desk.acc/calculator.s b/desk.acc/calculator.s
index 8152ba6..8775295 100644
--- a/desk.acc/calculator.s
+++ b/desk.acc/calculator.s
@@ -2,7 +2,7 @@
 
         .include "apple2.inc"
         .include "../inc/apple2.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"
 
diff --git a/desk.acc/date.s b/desk.acc/date.s
index 23e19bf..25b1a7a 100644
--- a/desk.acc/date.s
+++ b/desk.acc/date.s
@@ -3,7 +3,7 @@
         .include "apple2.inc"
         .include "../inc/apple2.inc"
         .include "../inc/prodos.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"
 
diff --git a/desk.acc/eyes.s b/desk.acc/eyes.s
index 3a6ac25..7ef7cb2 100644
--- a/desk.acc/eyes.s
+++ b/desk.acc/eyes.s
@@ -2,7 +2,7 @@
 
         .include "apple2.inc"
         .include "../inc/apple2.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"
         .include "../inc/fp_macros.inc"
diff --git a/desk.acc/key.caps.s b/desk.acc/key.caps.s
index 97f5a91..64af79b 100644
--- a/desk.acc/key.caps.s
+++ b/desk.acc/key.caps.s
@@ -2,7 +2,7 @@
 
         .include "apple2.inc"
         .include "../inc/apple2.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"
 
diff --git a/desk.acc/puzzle.s b/desk.acc/puzzle.s
index cdbd782..f55e4e7 100644
--- a/desk.acc/puzzle.s
+++ b/desk.acc/puzzle.s
@@ -2,7 +2,7 @@
 
         .include "apple2.inc"
         .include "../inc/apple2.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"
 
diff --git a/desk.acc/run.basic.here.s b/desk.acc/run.basic.here.s
index 4dd7966..e2a94e6 100644
--- a/desk.acc/run.basic.here.s
+++ b/desk.acc/run.basic.here.s
@@ -11,7 +11,7 @@
         .include "apple2.inc"
         .include "../inc/apple2.inc"
         .include "../inc/prodos.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"
 
diff --git a/desk.acc/screen.dump.s b/desk.acc/screen.dump.s
index 91f479f..4acab5d 100644
--- a/desk.acc/screen.dump.s
+++ b/desk.acc/screen.dump.s
@@ -3,7 +3,7 @@
         .include "apple2.inc"
         .include "../inc/apple2.inc"
         .include "../inc/prodos.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"
 
diff --git a/desk.acc/screen.saver.s b/desk.acc/screen.saver.s
index badbaf0..66d4214 100644
--- a/desk.acc/screen.saver.s
+++ b/desk.acc/screen.saver.s
@@ -2,7 +2,7 @@
 
         .include "apple2.inc"
         .include "../inc/apple2.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"
 
diff --git a/desk.acc/sort.directory.s b/desk.acc/sort.directory.s
index fd5ab57..eff2d8d 100644
--- a/desk.acc/sort.directory.s
+++ b/desk.acc/sort.directory.s
@@ -3,7 +3,7 @@
         .include "apple2.inc"
         .include "../inc/apple2.inc"
         .include "../inc/prodos.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"
 
diff --git a/desk.acc/this.apple.s b/desk.acc/this.apple.s
index 24f9c39..704725f 100644
--- a/desk.acc/this.apple.s
+++ b/desk.acc/this.apple.s
@@ -3,7 +3,7 @@
         .include "apple2.inc"
         .include "../inc/apple2.inc"
         .include "../inc/prodos.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"
 
diff --git a/desktop/Makefile b/desktop/Makefile
index 05e801d..6c1fc0f 100644
--- a/desktop/Makefile
+++ b/desktop/Makefile
@@ -5,7 +5,7 @@ CCFLAGS = --config asm.cfg
 
 OUTDIR = out
 
-HEADERS = $(wildcard ../*.inc) $(wildcard ../inc/*.inc) $(wildcard *.inc)
+HEADERS = $(wildcard ../*.inc) $(wildcard ../inc/*.inc) $(wildcard ../mgtk/*.inc) $(wildcard *.inc)
 
 SEGMENTS = loader mgtk desktop
 
@@ -23,6 +23,9 @@ clean:
 	rm -f $(OUTDIR)/*.built
 	rm -f $(TARGETS)
 
+$(OUTDIR)/mgtk.o: ../mgtk/mgtk.s $(HEADERS)
+	$(CC65)/ca65 $(CAFLAGS) --listing $(basename $@).list -o $@ $<
+
 $(OUTDIR)/desktop.o: desktop.s $(HEADERS) desktop_* ovl*.s
 	$(CC65)/ca65 $(CAFLAGS) --listing $(basename $@).list -o $@ $<
 
diff --git a/desktop/README.md b/desktop/README.md
index 88cc4c4..a0e319a 100644
--- a/desktop/README.md
+++ b/desktop/README.md
@@ -79,7 +79,7 @@ run.
 
 `mgtk.s`
 
-Aux $4000-$8580 is the [MouseGraphics ToolKit](../MGTK.md) - a
+Aux $4000-$8580 is the [MouseGraphics ToolKit](../mgtk/MGTK.md) - a
 GUI library used for the DeskTop application.
 
 Since this resides in Aux memory, DeskTop spends most of its time
diff --git a/desktop/desktop.s b/desktop/desktop.s
index 835026f..d5ee991 100644
--- a/desktop/desktop.s
+++ b/desktop/desktop.s
@@ -3,7 +3,7 @@
         .include "apple2.inc"
         .include "../inc/apple2.inc"
         .include "../inc/prodos.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"
 
diff --git a/CodingStyle.md b/docs/CodingStyle.md
similarity index 100%
rename from CodingStyle.md
rename to docs/CodingStyle.md
diff --git a/MGTK.md b/mgtk/MGTK.md
similarity index 100%
rename from MGTK.md
rename to mgtk/MGTK.md
diff --git a/mgtk/README.md b/mgtk/README.md
new file mode 100644
index 0000000..4abaa25
--- /dev/null
+++ b/mgtk/README.md
@@ -0,0 +1,7 @@
+# MouseGraphics ToolKit
+
+* `mgtk.inc` - header file to include
+
+* `mgtk.s` - toolkit source - build as part of application
+
+* `MGTK.md` - ToolKit documentation
diff --git a/mgtk.inc b/mgtk/mgtk.inc
similarity index 100%
rename from mgtk.inc
rename to mgtk/mgtk.inc
diff --git a/desktop/mgtk.s b/mgtk/mgtk.s
similarity index 99%
rename from desktop/mgtk.s
rename to mgtk/mgtk.s
index e1aff16..1aa0b9e 100644
--- a/desktop/mgtk.s
+++ b/mgtk/mgtk.s
@@ -3,8 +3,7 @@
         .include "apple2.inc"
         .include "../inc/apple2.inc"
         .include "../inc/prodos.inc"
-        .include "../mgtk.inc"
-        .include "../desktop.inc"
+        .include "mgtk.inc"
         .include "../macros.inc"
 
 ;;; ============================================================
diff --git a/preview/show.font.file.s b/preview/show.font.file.s
index 846e452..02cbdbd 100644
--- a/preview/show.font.file.s
+++ b/preview/show.font.file.s
@@ -5,7 +5,7 @@
         .include "../macros.inc"
         .include "../inc/apple2.inc"
         .include "../inc/prodos.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
 
 ;;; ============================================================
diff --git a/preview/show.image.file.s b/preview/show.image.file.s
index bc96dcd..e7a73f5 100644
--- a/preview/show.image.file.s
+++ b/preview/show.image.file.s
@@ -3,7 +3,7 @@
         .include "apple2.inc"
         .include "../inc/apple2.inc"
         .include "../inc/prodos.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"
 
diff --git a/preview/show.text.file.s b/preview/show.text.file.s
index c7beadd..a0b1245 100644
--- a/preview/show.text.file.s
+++ b/preview/show.text.file.s
@@ -3,7 +3,7 @@
         .include "apple2.inc"
         .include "../inc/apple2.inc"
         .include "../inc/prodos.inc"
-        .include "../mgtk.inc"
+        .include "../mgtk/mgtk.inc"
         .include "../desktop.inc"
         .include "../macros.inc"