diff --git a/ffi/export.h b/ffi/export.h
index 31022f1..f09f8a4 100644
--- a/ffi/export.h
+++ b/ffi/export.h
@@ -159,6 +159,7 @@ extern "C" {
 
 MLLIB_PUBLIC(void mltonFramebufferSizeCallback (Int32 x0, Int32 x1);)
 MLLIB_PUBLIC(void mltonCharCallback (Word32 x0);)
+MLLIB_PUBLIC(void mltonKeyCallback (Int32 x0, Int32 x1, Int32 x2, Int32 x3);)
 
 #undef MLLIB_PRIVATE
 #undef MLLIB_PUBLIC
diff --git a/ffi/glfw-input.c b/ffi/glfw-input.c
index ab99bdd..5d5f7dc 100644
--- a/ffi/glfw-input.c
+++ b/ffi/glfw-input.c
@@ -6,6 +6,7 @@
 int PRESS = GLFW_PRESS;
 int REPEAT = GLFW_REPEAT;
 int RELEASE = GLFW_RELEASE;
+int KEY_ESC = GLFW_KEY_ESCAPE;
 
 void framebufferSizeCallback(GLFWwindow* window, int width, int height) {
   glViewport(0, 0, width, height);
@@ -24,3 +25,11 @@ void setCharCallback(GLFWwindow* window) {
   glfwSetCharCallback(window, charCallback);
 }
 
+void keyCallback(GLFWwindow *window, int key, int scancode, int action, int mods) {
+  mltonKeyCallback(key, scancode, action, mods);
+}
+
+void setKeyCallback(GLFWwindow *window) {
+  glfwSetKeyCallback(window, keyCallback);
+}
+
diff --git a/ffi/glfw-input.sml b/ffi/glfw-input.sml
index 4e73e9d..cf437dd 100644
--- a/ffi/glfw-input.sml
+++ b/ffi/glfw-input.sml
@@ -24,4 +24,13 @@ struct
     _export "mltonCharCallback" public : (Word32.word -> unit) -> unit;
   val setCharCallback =
     _import "setCharCallback" public : window -> unit;
+
+  val exportKeyCallback =
+    _export "mltonKeyCallback" public : (int * int * int * int -> unit) -> unit;
+  val setKeyCallback =
+    _import "setKeyCallback" public : window -> unit;
+
+  val (KEY_ESC, _) =
+    _symbol "KEY_ESC" public : ( unit -> int ) * ( int -> unit );
+  val KEY_ESC = KEY_ESC ()
 end
diff --git a/shell/shell.sml b/shell/shell.sml
index 80cc9ba..c35de5f 100644
--- a/shell/shell.sml
+++ b/shell/shell.sml
@@ -14,6 +14,16 @@ struct
       Mailbox.send (inputMailbox, CHAR_EVENT chr)
     end
 
+  fun keyCallback inputMailbox (key, scancode, action, mods) =
+    let
+      open Input
+    in
+      if key = KEY_ESC andalso action = PRESS andalso mods = 0 then
+        Mailbox.send (inputMailbox, InputMsg.KEY_ESC)
+      else
+        ()
+    end
+
   fun registerCallbacks (inputMailbox, window) =
     let
       val resizeCallback = frameBufferSizeCallback inputMailbox
@@ -23,6 +33,10 @@ struct
       val charCallback = charCallback inputMailbox
       val () = Input.exportCharCallback charCallback
       val () = Input.setCharCallback window
+
+      val keyCallback = keyCallback inputMailbox
+      val () = Input.exportKeyCallback keyCallback
+      val () = Input.setKeyCallback window
     in
       ()
     end
diff --git a/shf b/shf
index e2b4549..6b77591 100755
Binary files a/shf and b/shf differ