diff --git a/Makefile b/Makefile
index 68afd3c..f9ce9bf 100644
--- a/Makefile
+++ b/Makefile
@@ -48,9 +48,21 @@ all-cgtests: $(cgtests_targets)
 clean-cgtests:
 	rm -f cgtests/cgtest?? cgtests/*.tock.*
 
+#Haddock does allow you to customise the description section of a file, but only with more Haskell comments
+#Since I want to use an HTML description (with links to SVG using object tags) I have to perform the following hack
+#to use my own custom HTML description.  Fixes to make the hack nicer are welcome :-)
+
 haddock:
 	@mkdir -p doc
-	haddock -o doc --html $(filter-out LexOccam.hs LexRain.hs,$(sources))
+	@echo "putmycustomdocumentationhere" > .temp-haddock-file
+	haddock -o doc --html -p temp-haddock-file -t Tock $(filter-out LexOccam.hs LexRain.hs,$(sources))
+	cp docextra/*.svg doc/
+	@rm .temp-haddock-file
+	@grep -B 10000 putmycustomdocumentationhere doc/index.html | sed "s/putmycustomdocumentationhere//" > doc/index.html-2	
+	@cat docextra/description.html >> doc/index.html-2
+	@grep -A 10000 putmycustomdocumentationhere doc/index.html | tail -n +2 >> doc/index.html-2
+	@rm doc/index.html
+	@mv doc/index.html-2 doc/index.html
 
 clean:
 	rm -f $(targets) *.o *.hi
diff --git a/docextra/description.html b/docextra/description.html
new file mode 100644
index 0000000..4c42840
--- /dev/null
+++ b/docextra/description.html
@@ -0,0 +1,14 @@
+<p>
+This is the generated API documentation for the Tock compiler.
+</p>
+
+<h3>Tock Passes</h3>
+<p>
+Below is a rough diagram of the structure of Tock.  On the left are the front-ends, in the middle are the common passes, and on the right are the back-ends.
+</p>
+<object data="tock-passes.svg" width="800" height="400">
+<p>
+<i>In order to view this image you need an SVG viewer.  The most recent versions of Firefox and Opera both have in-built SVG viewers. 
+For Internet Explorer, you will need to install the <a href="http://www.adobe.com/svg/viewer/install/">Adobe SVG Viewer</a>.</i>
+</p>
+</object>
diff --git a/docextra/tock-passes.svg b/docextra/tock-passes.svg
new file mode 100644
index 0000000..d6de8cd
--- /dev/null
+++ b/docextra/tock-passes.svg
@@ -0,0 +1,398 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) and then hand-edited -->
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://web.resource.org/cc/"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:xlink="http://www.w3.org/1999/xlink"      
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   viewBox="0 0 720 360"
+   id="svg2"   
+   inkscape:version="0.45.1"   
+   inkscape:output_extension="org.inkscape.output.svg.inkscape"
+   version="1.0">
+  <defs
+     id="defs4" >
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+      rect {        
+		fill:#000000;
+		fill-opacity:0;
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+	  text.label {
+		font-size:12px;
+		font-style:normal;
+		font-weight:normal;
+		fill:#000000;
+		fill-opacity:1;
+		stroke:none;
+		stroke-width:1px;
+		stroke-linecap:butt;
+		stroke-linejoin:miter;
+		stroke-opacity:1;
+		font-family:Bitstream Vera Sans;
+	  }
+	  text.module {
+		font-size:12px;
+		font-style:normal;
+		font-weight:normal;
+		fill:#0000ff;
+		fill-opacity:1;
+		stroke:none;
+		stroke-width:1px;
+		stroke-linecap:butt;
+		stroke-linejoin:miter;
+		stroke-opacity:1;
+		font-family:Bitstream Vera Sans;
+		text-align:center;
+		text-anchor:middle;
+	  }
+	  path {
+		fill:none;
+		fill-rule:evenodd;
+		stroke:#000000;
+		stroke-width:1px;
+		stroke-linecap:butt;
+		stroke-linejoin:miter;
+		stroke-opacity:1;
+		display:inline
+	  }
+    ]]></style>
+  </defs>
+  <metadata
+     id="metadata7">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <cc:license
+           rdf:resource="" />
+        <dc:title>Tock Passes Diagram</dc:title>
+        <dc:date>30/08/07</dc:date>
+        <dc:creator>
+          <cc:Agent>
+            <dc:title>Neil Brown</dc:title>
+          </cc:Agent>
+        </dc:creator>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <g
+     inkscape:label="Layer 1"
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+         id="rect2160"
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+      <text
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+         y="10"
+         x="0"
+         class="label"         
+         xml:space="preserve">occam frontend</text>
+      <a         
+         xlink:href="ParseOccam.html"
+         xlink:show="new"
+         id="a4113">
+      <rect
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+        <text
+           xml:space="preserve"           
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+      <text
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+         y="240"
+         x="0"     
+		 class="label"
+         xml:space="preserve">Rain frontend</text>
+	  <a         
+         xlink:href="RainParse.html"
+         xlink:show="new"
+         id="a4147">        
+      <rect
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+	  <a         
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+         xlink:show="new"
+         id="a4161">        
+      <rect
+         y="270"
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+         id="rect4159"
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+          <text
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+             y="300"
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+      </a>
+      <path
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+    <path       
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+    <path       
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+      <text
+         id="text4173"
+         y="40"
+         x="300"
+         class="label"
+         xml:space="preserve">Shared passes</text>      
+	  <a         
+         xlink:href="SimplifyTypes.html"
+         xlink:show="new"
+         id="a4181">
+      <rect         
+         id="rect4179"
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+      </a>
+      <path
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+	  <path
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+      <rect         
+         id="rect4179"
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+      </a>
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+      <text
+         id="text4299"
+         y="230"
+         x="530"
+         class="label"
+         xml:space="preserve">C++/C++CSP backend</text>
+	  <a         
+         xlink:href="GenerateCPPCSP.html"
+         xlink:show="new"
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+      <rect
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