diff --git a/packages/ember-application/lib/system/application.js b/packages/ember-application/lib/system/application.js
index db820688839..fb2c25f9add 100644
--- a/packages/ember-application/lib/system/application.js
+++ b/packages/ember-application/lib/system/application.js
@@ -276,20 +276,23 @@ var Application = Namespace.extend(DeferredMixin, {
     Ember.libraries.registerCoreLibrary('Handlebars' + (EmberHandlebars.compile ? '' : '-runtime'), EmberHandlebars.VERSION);
     Ember.libraries.registerCoreLibrary('jQuery', jQuery().jquery);
 
-    if ( Ember.LOG_VERSION ) {
-      Ember.LOG_VERSION = false; // we only need to see this once per Application#init
+    if (Ember.LOG_VERSION) {
+      // we only need to see this once per Application#init
+      Ember.LOG_VERSION = false;
+      var libs = Ember.libraries._registry;
 
-      var nameLengths = EnumerableUtils.map(Ember.libraries, function(item) {
-        return get(item, "name.length");
+      var nameLengths = EnumerableUtils.map(libs, function(item) {
+        return get(item, 'name.length');
       });
 
       var maxNameLength = Math.max.apply(this, nameLengths);
 
       Ember.debug('-------------------------------');
-      Ember.libraries.each(function(name, version) {
-        var spaces = new Array(maxNameLength - name.length + 1).join(" ");
-        Ember.debug([name, spaces, ' : ', version].join(""));
-      });
+      for (var i = 0, l = libs.length; i < l; i++) {
+        var lib = libs[i];
+        var spaces = new Array(maxNameLength - lib.name.length + 1).join(' ');
+        Ember.debug([lib.name, spaces, ' : ', lib.version].join(''));
+      }
       Ember.debug('-------------------------------');
     }
   },
diff --git a/packages/ember-metal/lib/libraries.js b/packages/ember-metal/lib/libraries.js
index 627cf73f882..c15115f4229 100644
--- a/packages/ember-metal/lib/libraries.js
+++ b/packages/ember-metal/lib/libraries.js
@@ -1,45 +1,70 @@
-// Provides a way to register library versions with ember.
+import Ember from "ember-metal/core";
 import {
   forEach,
   indexOf
 } from "ember-metal/enumerable_utils";
 
-var libraries = function() {
-  var _libraries   = [];
-  var coreLibIndex = 0;
+/**
+  Helper class that allows you to register your library with Ember.
 
-  var getLibrary = function(name) {
-    for (var i = 0; i < _libraries.length; i++) {
-      if (_libraries[i].name === name) {
-        return _libraries[i];
+  Singleton created at `Ember.libraries`.
+
+  @class Libraries
+  @constructor
+  @private
+*/
+function Libraries() {
+  this._registry = [];
+  this._coreLibIndex = 0;
+}
+
+Libraries.prototype = {
+  constructor: Libraries,
+
+  _getLibraryByName: function(name) {
+    var libs = this._registry;
+    var count = libs.length;
+
+    for (var i = 0; i < count; i++) {
+      if (libs[i].name === name) {
+        return libs[i];
       }
     }
-  };
+  },
 
-  _libraries.register = function(name, version) {
-    if (!getLibrary(name)) {
-      _libraries.push({name: name, version: version});
-    }
-  };
+  register: function(name, version, isCoreLibrary) {
+    var index = this._registry.length;
 
-  _libraries.registerCoreLibrary = function(name, version) {
-    if (!getLibrary(name)) {
-      _libraries.splice(coreLibIndex++, 0, {name: name, version: version});
+    if (!this._getLibraryByName(name)) {
+      if (isCoreLibrary) {
+        index = this._coreLibIndex++;
+      }
+      this._registry.splice(index, 0, { name: name, version: version });
+    } else {
+      Ember.warn('Library "' + name + '" is already registered with Ember.');
     }
-  };
+  },
+
+  registerCoreLibrary: function(name, version) {
+    this.register(name, version, true);
+  },
 
-  _libraries.deRegister = function(name) {
-    var lib = getLibrary(name);
-    if (lib) _libraries.splice(indexOf(_libraries, lib), 1);
-  };
+  deRegister: function(name) {
+    var lib = this._getLibraryByName(name);
+    var index;
 
-  _libraries.each = function (callback) {
-    forEach(_libraries, function(lib) {
+    if (lib) {
+      index = indexOf(this._registry, lib);
+      this._registry.splice(index, 1);
+    }
+  },
+
+  each: function(callback) {
+    Ember.deprecate('Using Ember.libraries.each() is deprecated. Access to a list of registered libraries is currently a private API. If you are not knowingly accessing this method, your out-of-date Ember Inspector may be doing so.');
+    forEach(this._registry, function(lib) {
       callback(lib.name, lib.version);
     });
-  };
-
-  return _libraries;
-}();
+  }
+};
 
-export default libraries;
+export default Libraries;
diff --git a/packages/ember-metal/lib/main.js b/packages/ember-metal/lib/main.js
index 1c85ca69173..d1492036e0f 100644
--- a/packages/ember-metal/lib/main.js
+++ b/packages/ember-metal/lib/main.js
@@ -160,7 +160,7 @@ import {
   oneWay
 } from "ember-metal/binding";
 import run from "ember-metal/run_loop";
-import libraries from "ember-metal/libraries";
+import Libraries from "ember-metal/libraries";
 import isNone from 'ember-metal/is_none';
 import isEmpty from 'ember-metal/is_empty';
 import isBlank from 'ember-metal/is_blank';
@@ -311,7 +311,7 @@ Ember.isGlobalPath = isGlobalPath;
 
 Ember.run = run;
 
-Ember.libraries = libraries;
+Ember.libraries = new Libraries();
 Ember.libraries.registerCoreLibrary('Ember', Ember.VERSION);
 
 Ember.isNone = isNone;
diff --git a/packages/ember-metal/tests/libraries_test.js b/packages/ember-metal/tests/libraries_test.js
index 57dc727b79c..8256ab83423 100644
--- a/packages/ember-metal/tests/libraries_test.js
+++ b/packages/ember-metal/tests/libraries_test.js
@@ -1,50 +1,93 @@
-import libraries from "ember-metal/libraries";
+/* globals EmberDev */
+import Libraries from "ember-metal/libraries";
 
-var libs = libraries;
+var libs, registry;
 
-test('Ember registers itself', function() {
-  equal(libs[0].name, "Ember");
+QUnit.module('Libraries registry', {
+  setup: function() {
+    libs = new Libraries();
+    registry = libs._registry;
+  },
+
+  teardown: function() {
+    libs = null;
+    registry = null;
+  }
 });
 
 test('core libraries come before other libraries', function() {
-  var l = libs.length;
-
-  libs.register("my-lib", "2.0.0a");
-  libs.registerCoreLibrary("DS", "1.0.0-beta.2");
+  expect(2);
 
-  equal(libs[l].name, "DS");
-  equal(libs[l+1].name, "my-lib");
+  libs.register('my-lib', '2.0.0a');
+  libs.registerCoreLibrary('DS', '1.0.0-beta.2');
 
-  libs.deRegister("my-lib");
-  libs.deRegister("DS");
+  equal(registry[0].name, 'DS');
+  equal(registry[1].name, 'my-lib');
 });
 
 test('only the first registration of a library is stored', function() {
-  var l = libs.length;
+  expect(3);
+
+  libs.register('magic', 1.23);
+  libs.register('magic', 2.23);
+
+  equal(registry[0].name, 'magic');
+  equal(registry[0].version, 1.23);
+  equal(registry.length, 1);
+});
+
+test('attempting to register a library that is already registered warns you', function() {
+  if (EmberDev && EmberDev.runningProdBuild){
+    ok(true, 'Logging does not occur in production builds');
+    return;
+  }
+
+  expect(1);
 
-  libs.register("magic", 1.23);
-  libs.register("magic", 2.23);
-  libs.register("magic", 3.23);
+  var oldWarn = Ember.warn;
+  libs.register('magic', 1.23);
 
-  equal(libs[l].name, "magic");
-  equal(libs[l].version, 1.23);
-  equal(libs.length, l+1);
+  Ember.warn = function(msg, test) {
+    if (!test) {
+      equal(msg, 'Library "magic" is already registered with Ember.');
+    }
+  };
 
-  libs.deRegister("magic");
+  // Should warn us
+  libs.register('magic', 2.23);
+
+  Ember.warn = oldWarn;
 });
 
 test('libraries can be de-registered', function() {
-  var l = libs.length;
-
-  libs.register("lib1", "1.0.0b");
-  libs.register("lib2", "1.0.0b");
-  libs.register("lib3", "1.0.0b");
+  expect(2);
 
-  libs.deRegister("lib1");
-  libs.deRegister("lib3");
+  libs.register('lib1', '1.0.0b');
+  libs.register('lib2', '1.0.0b');
+  libs.register('lib3', '1.0.0b');
 
-  equal(libs[l].name, "lib2");
-  equal(libs.length, l+1);
+  libs.deRegister('lib1');
+  libs.deRegister('lib3');
 
-  libs.deRegister("lib2");
+  equal(registry[0].name, 'lib2');
+  equal(registry.length, 1);
 });
+
+
+test('Libraries#each allows us to loop through each registered library (but is deprecated)', function() {
+  expect(5);
+
+  var items = [{ name: 'lib1', version: '1.0.0' }, { name: 'lib2', version: '2.0.0' }];
+
+  for (var i = 0, l = items.length; i < l; i++) {
+    libs.register(items[i].name, items[i].version);
+  }
+
+  expectDeprecation(function() {
+    libs.each(function (name, version) {
+      var expectedLib = items.shift();
+      equal(expectedLib.name, name);
+      equal(expectedLib.version, version);
+    });
+  }, 'Using Ember.libraries.each() is deprecated. Access to a list of registered libraries is currently a private API. If you are not knowingly accessing this method, your out-of-date Ember Inspector may be doing so.');
+});
\ No newline at end of file
diff --git a/packages/ember-metal/tests/main_test.js b/packages/ember-metal/tests/main_test.js
new file mode 100644
index 00000000000..e4fcf6c14d7
--- /dev/null
+++ b/packages/ember-metal/tests/main_test.js
@@ -0,0 +1,10 @@
+import Ember from "ember-metal/core";
+
+QUnit.module('ember-metal/core/main');
+
+test('Ember registers itself', function() {
+  var lib = Ember.libraries._registry[0];
+
+  equal(lib.name, 'Ember');
+  equal(lib.version, Ember.VERSION);
+});
\ No newline at end of file