diff --git a/docs/lib-m_mirror.md b/docs/lib-m_mirror.md
new file mode 100644
index 00000000..6280c53f
--- /dev/null
+++ b/docs/lib-m_mirror.md
@@ -0,0 +1,23 @@
+# m_mirror
+
+Generate a 4x4 transformation matrix which can pass into `multmatrix` to mirror the child element on a plane through the origin. 
+
+**Since:** 1.1
+
+## Parameters
+
+- `v` : The normal vector of a plane intersecting the origin through which to mirror the object.
+
+## Examples
+
+	include <m_mirror.scad>;
+
+	rotate([0, 0, 10]) 
+		cube([3, 2, 1]);
+		
+	multmatrix(m_mirror([1, 1, 0]))
+		rotate([0, 0, 10]) 
+			cube([3, 2, 1]);
+
+![m_mirror](images/lib-m_mirror-1.JPG)
+