diff --git a/inspect.lua b/inspect.lua
index 4b654b2..c7179d1 100644
--- a/inspect.lua
+++ b/inspect.lua
@@ -28,6 +28,8 @@ local inspect ={
   ]]
 }
 
+local tostring = tostring
+
 inspect.KEY       = setmetatable({}, {__tostring = function() return 'inspect.KEY' end})
 inspect.METATABLE = setmetatable({}, {__tostring = function() return 'inspect.METATABLE' end})
 
@@ -202,7 +204,7 @@ function Inspector:puts(...)
   local len    = #buffer
   for i=1, #args do
     len = len + 1
-    buffer[len] = tostring(args[i])
+    buffer[len] = args[i]
   end
 end
 
@@ -228,7 +230,7 @@ function Inspector:getId(v)
     self.maxIds[tv] = id
     self.ids[tv][v] = id
   end
-  return id
+  return tostring(id)
 end
 
 function Inspector:putKey(k)
diff --git a/spec/inspect_spec.lua b/spec/inspect_spec.lua
index 78b0a7b..23868f0 100644
--- a/spec/inspect_spec.lua
+++ b/spec/inspect_spec.lua
@@ -417,4 +417,13 @@ describe( 'inspect', function()
       end)
     end)
   end)
+
+  it('allows changing the global tostring', function()
+    local save = _G.tostring
+    _G.tostring = inspect 
+    local s = tostring({1, 2, 3})
+    _G.tostring = save    
+    assert.equals("{ 1, 2, 3 }", s)
+  end) 
+
 end)