diff --git a/libraries.api.php b/libraries.api.php
index 66fa772..a30f44c 100644
--- a/libraries.api.php
+++ b/libraries.api.php
@@ -118,10 +118,14 @@
  *     - $variant: If the $library array belongs to a certain variant (see
  *       above), a string containing the variant name. NULL, otherwise.
  *     Valid callback groups are:
- *     - prepare: Callbacks registered in this group are applied as soon as the
+ *     - info: Callbacks registered in this group are applied as soon as the
  *       library information has been retrieved via hook_libraries_info() or
  *       info files.
- *     - detect: Callbacks registered in this group are applied as soon as
+ *     - pre detect: Callbacks registered in this group are applied when a
+ *       library is about to be detected, before the version callback is
+ *       invoked. At this point the following additional information is available:
+ *       - $library['library path']: The path on the file system to the library.
+ *     - post detect: Callbacks registered in this group are applied as soon as
  *       library detection has been completed. At this point the library
  *       contains the version-specific information, if specified, and following
  *       additional information is available:
diff --git a/libraries.module b/libraries.module
index 2c864d9..4c44a18 100644
--- a/libraries.module
+++ b/libraries.module
@@ -155,7 +155,7 @@ function libraries_scan_info_files() {
  *
  * @param $group
  *   A string containing the group of callbacks that is to be applied. Should be
- *   either 'prepare', 'detect', or 'load'.
+ *   either 'info', 'pre detect', 'post detect', or 'load'.
  * @param $library
  *   An array of library information, passed by reference.
  */
@@ -250,9 +250,9 @@ function libraries_info($name = NULL) {
     // Allow modules to alter the registered libraries.
     drupal_alter('libraries_info', $libraries);
 
-    // Invoke callbacks in the 'prepare' group.
+    // Invoke callbacks in the 'info' group.
     foreach ($libraries as &$properties) {
-      libraries_invoke('prepare', $properties);
+      libraries_invoke('info', $properties);
     }
   }
 
@@ -287,8 +287,9 @@ function libraries_info_defaults(&$library, $name) {
     'callbacks' => array(),
   );
   $library['callbacks'] += array(
-    'prepare' => array(),
-    'detect' => array(),
+    'info' => array(),
+    'pre detect' => array(),
+    'post detect' => array(),
     'load' => array(),
   );
   return $library;
@@ -342,6 +343,9 @@ function libraries_detect($name) {
     return $library;
   }
 
+  // Invoke callbacks in the 'pre detect' group.
+  libraries_invoke('pre detect', $library);
+
   // Detect library version, if not hardcoded.
   if (!isset($library['version'])) {
     // We support both a single parameter, which is an associative array, and an
@@ -417,8 +421,8 @@ function libraries_detect($name) {
   // If we end up here, the library should be usable.
   $library['installed'] = TRUE;
 
-  // Invoke callbacks in the 'detect' group.
-  libraries_invoke('detect', $library);
+  // Invoke callbacks in the 'post detect' group.
+  libraries_invoke('post detect', $library);
 
   return $library;
 }
diff --git a/tests/libraries.test b/tests/libraries.test
index 785b8ae..a0d67d0 100644
--- a/tests/libraries.test
+++ b/tests/libraries.test
@@ -148,57 +148,66 @@ class LibrariesTestCase extends DrupalWebTestCase {
         '1' => array(
           'variants' => array(
             'example_variant' => array(
-              'prepare callback' => 'not applied',
-              'detect callback' => 'not applied',
+              'info callback' => 'not applied',
+              'pre detect callback' => 'not applied',
+              'post detect callback' => 'not applied',
               'load callback' => 'not applied',
             ),
           ),
-          'prepare callback' => 'not applied',
-          'detect callback' => 'not applied',
+          'info callback' => 'not applied',
+          'pre detect callback' => 'not applied',
+          'post detect callback' => 'not applied',
           'load callback' => 'not applied',
         ),
       ),
       'variants' => array(
         'example_variant' => array(
-          'prepare callback' => 'not applied',
-          'detect callback' => 'not applied',
+          'info callback' => 'not applied',
+          'pre detect callback' => 'not applied',
+          'post detect callback' => 'not applied',
           'load callback' => 'not applied',
         ),
       ),
       'callbacks' => array(
-        'prepare' => array('_libraries_test_prepare_callback'),
-        'detect' => array('_libraries_test_detect_callback'),
+        'info' => array('_libraries_test_info_callback'),
+        'pre detect' => array('_libraries_test_pre_detect_callback'),
+        'post detect' => array('_libraries_test_post_detect_callback'),
         'load' => array('_libraries_test_load_callback'),
       ),
-      'prepare callback' => 'not applied',
-      'detect callback' => 'not applied',
+      'info callback' => 'not applied',
+      'pre detect callback' => 'not applied',
+      'post detect callback' => 'not applied',
       'load callback' => 'not applied',
       'module' => 'libraries_test',
     );
     libraries_info_defaults($expected, 'example_callback');
 
-    // Test a callback in the 'prepare' phase.
-    $expected['prepare callback'] = 'applied (top-level)';
-    $expected['versions']['1']['prepare callback'] = 'applied (version 1)';
-    $expected['versions']['1']['variants']['example_variant']['prepare callback'] = 'applied (version 1, variant example_variant)';
-    $expected['variants']['example_variant']['prepare callback'] = 'applied (variant example_variant)';
+    // Test a callback in the 'info' group.
+    $expected['info callback'] = 'applied (top-level)';
+    $expected['versions']['1']['info callback'] = 'applied (version 1)';
+    $expected['versions']['1']['variants']['example_variant']['info callback'] = 'applied (version 1, variant example_variant)';
+    $expected['variants']['example_variant']['info callback'] = 'applied (variant example_variant)';
     $library = libraries_info('example_callback');
     $this->verbose('Expected:<pre>' . var_export($expected, TRUE) . '</pre>');
     $this->verbose('Actual:<pre>' . var_export($library, TRUE) . '</pre>');
     $this->assertEqual($library, $expected, 'Prepare callback was applied correctly.');
 
-    // Test a callback in the 'detect' phase.
+    // Test a callback in the 'pre detect' and 'post detect' phase.
     // Successfully detected libraries should only contain version information
     // for the detected version and thus, be marked as installed.
     unset($expected['versions']);
     $expected['installed'] = TRUE;
     // Additionally, version-specific properties of the detected version are
     // supposed to override the corresponding top-level properties.
-    $expected['prepare callback'] = 'applied (version 1)';
+    $expected['info callback'] = 'applied (version 1)';
     $expected['variants']['example_variant']['installed'] = TRUE;
-    $expected['variants']['example_variant']['prepare callback'] = 'applied (version 1, variant example_variant)';
-    $expected['detect callback'] = 'applied (top-level)';
-    $expected['variants']['example_variant']['detect callback'] = 'applied (variant example_variant)';
+    $expected['variants']['example_variant']['info callback'] = 'applied (version 1, variant example_variant)';
+    // Version-overloading takes place after the 'pre detect' callbacks have
+    // been applied.
+    $expected['pre detect callback'] = 'applied (version 1)';
+    $expected['post detect callback'] = 'applied (top-level)';
+    $expected['variants']['example_variant']['pre detect callback'] = 'applied (version 1, variant example_variant)';
+    $expected['variants']['example_variant']['post detect callback'] = 'applied (variant example_variant)';
     $library = libraries_detect('example_callback');
     $this->verbose('Expected:<pre>' . var_export($expected, TRUE) . '</pre>');
     $this->verbose('Actual:<pre>' . var_export($library, TRUE) . '</pre>');
@@ -218,8 +227,9 @@ class LibrariesTestCase extends DrupalWebTestCase {
     drupal_static_reset('libraries_load');
     // Successfully loaded library variants are supposed to contain the specific
     // variant information only.
-    $expected['prepare callback'] = 'applied (version 1, variant example_variant)';
-    $expected['detect callback'] = 'applied (variant example_variant)';
+    $expected['info callback'] = 'applied (version 1, variant example_variant)';
+    $expected['pre detect callback'] = 'applied (version 1, variant example_variant)';
+    $expected['post detect callback'] = 'applied (variant example_variant)';
     $library = libraries_load('example_callback', 'example_variant');
     $this->verbose('Expected:<pre>' . var_export($expected, TRUE) . '</pre>');
     $this->verbose('Actual:<pre>' . var_export($library, TRUE) . '</pre>');
diff --git a/tests/libraries_test.module b/tests/libraries_test.module
index c1c454c..0f4999b 100644
--- a/tests/libraries_test.module
+++ b/tests/libraries_test.module
@@ -73,6 +73,45 @@ function libraries_test_libraries_info() {
     ),
   );
 
+  // Test all types of JavaScript and CSS supported by drupal_add_js() and
+  // drupal_add_css().
+  $libraries['example_js_css'] = array(
+    'name' => 'Example JavaScript and CSS',
+    'library path' => drupal_get_path('module', 'libraries') . '/tests/example',
+    'version' => 1,
+    'variants' => array(
+      'file' => array(
+        'files' => array(
+          'js' => array('example_1.js'),
+          'css' => array('example_1.css'),
+        ),
+      ),
+      'external' => array(
+        'files' => array(
+          'js' => array(url(NULL, array('absolute' => TRUE)) . '/' . drupal_get_path('module', 'libraries') . '/tests/example/example_1.js'),
+          'css' => array(url(NULL, array('absolute' => TRUE)) . '/' . drupal_get_path('module', 'libraries') . '/tests/example/example_1.css'),
+        ),
+      ),
+      'inline' => array(
+        'files' => array(
+          // This is the content of example_1.js.
+          'js' => array('$(".libraries-test-javascript").text("If this text shows up, example_1.js was loaded successfully.")'),
+          // This is the content of example_1.css.
+          'css' => array('.libraries-test-css{color:red;}'),
+        ),
+      ),
+      // There is no CSS equivalent of JavaScript settings.
+      'setting' => array(
+        'files' => array(
+          'js' => array(
+            array('librariesTest' => array('testSetting' => TRUE)),
+            'if(Drupal.settings.librariesTest.testSetting){$(".libraries-test-javascript").text("If this text shows up, example_1.js was loaded successfully.")}',
+          ),
+        ),
+      )
+    ),
+  );
+
   // Test loading of integration files.
   // Normally added by the corresponding module via hook_libraries_info_alter(),
   // these files should be automatically loaded when the library is loaded.
@@ -210,33 +249,38 @@ function libraries_test_libraries_info() {
         'variants' => array(
           'example_variant' => array(
             // These keys are for testing purposes only.
-            'prepare callback' => 'not applied',
-            'detect callback' => 'not applied',
+            'info callback' => 'not applied',
+            'pre detect callback' => 'not applied',
+            'post detect callback' => 'not applied',
             'load callback' => 'not applied',
           ),
         ),
         // These keys are for testing purposes only.
-        'prepare callback' => 'not applied',
-        'detect callback' => 'not applied',
+        'info callback' => 'not applied',
+        'pre detect callback' => 'not applied',
+        'post detect callback' => 'not applied',
         'load callback' => 'not applied',
       ),
     ),
     'variants' => array(
       'example_variant' => array(
         // These keys are for testing purposes only.
-        'prepare callback' => 'not applied',
-        'detect callback' => 'not applied',
+        'info callback' => 'not applied',
+        'pre detect callback' => 'not applied',
+        'post detect callback' => 'not applied',
         'load callback' => 'not applied',
       ),
     ),
     'callbacks' => array(
-      'prepare' => array('_libraries_test_prepare_callback'),
-      'detect' => array('_libraries_test_detect_callback'),
+      'info' => array('_libraries_test_info_callback'),
+      'pre detect' => array('_libraries_test_pre_detect_callback'),
+      'post detect' => array('_libraries_test_post_detect_callback'),
       'load' => array('_libraries_test_load_callback'),
     ),
     // These keys are for testing purposes only.
-    'prepare callback' => 'not applied',
-    'detect callback' => 'not applied',
+    'info callback' => 'not applied',
+    'pre detect callback' => 'not applied',
+    'post detect callback' => 'not applied',
     'load callback' => 'not applied',
   );
 
@@ -322,45 +366,37 @@ function _libraries_test_return_installed($library, $name, $installed) {
 }
 
 /**
- * Sets the 'prepare callback' key.
- *
- * This function is used as a test callback for the 'prepare' callback group.
+ * Sets the 'info callback' key.
  *
- * @param $library
- *   An array of library information, which may be version- or variant-specific.
- *   Passed by reference.
- * @param $version
- *   The version the library information passed in $library belongs to, or NULL
- *   if the passed library information is not version-specific.
- * @param $variant
- *   The variant the library information passed in $library belongs to, or NULL
- *   if the passed library information is not variant-specific.
+ * This function is used as a test callback for the 'info' callback group.
  *
  * @see _libraries_test_callback()
  */
-function _libraries_test_prepare_callback(&$library, $version, $variant) {
-  _libraries_test_callback($library, $version, $variant, 'prepare');
+function _libraries_test_info_callback(&$library, 
+$version, $variant) {
+  _libraries_test_callback($library, $version, $variant, 'info');
 }
 
 /**
- * Sets the 'detect callback' key.
+ * Sets the 'pre detect callback' key.
  *
- * This function is used as a test callback for the 'detect' callback group.
+ * This function is used as a test callback for the 'pre detect' callback group.
  *
- * @param $library
- *   An array of library information, which may be version- or variant-specific.
- *   Passed by reference.
- * @param $version
- *   The version the library information passed in $library belongs to, or NULL
- *   if the passed library information is not version-specific.
- * @param $variant
- *   The variant the library information passed in $library belongs to, or NULL
- *   if the passed library information is not variant-specific.
+ * @see _libraries_test_callback()
+ */
+function _libraries_test_pre_detect_callback(&$library, $version, $variant) {
+  _libraries_test_callback($library, $version, $variant, 'pre detect');
+}
+
+/**
+ * Sets the 'post detect callback' key.
+ *
+ * This function is used as a test callback for the 'post detect callback group.
  *
  * @see _libraries_test_callback()
  */
-function _libraries_test_detect_callback(&$library, $version, $variant) {
-  _libraries_test_callback($library, $version, $variant, 'detect');
+function _libraries_test_post_detect_callback(&$library, $version, $variant) {
+  _libraries_test_callback($library, $version, $variant, 'post detect');
 }
 
 /**
@@ -456,6 +492,30 @@ function libraries_test_menu() {
     'page arguments' => array('example_versions_and_variants', 'example_variant_2'),
     'access callback' => TRUE,
   );
+  $items['libraries_test/js_css/file'] = array(
+    'title' => 'Test JavaScript and CSS: Local files',
+    'page callback' => '_libraries_test_load',
+    'page arguments' => array('example_js_css', 'file'),
+    'access callback' => TRUE,
+  );
+  $items['libraries_test/js_css/external'] = array(
+    'title' => 'Test JavaScript and CSS: External files',
+    'page callback' => '_libraries_test_load',
+    'page arguments' => array('example_js_css', 'external'),
+    'access callback' => TRUE,
+  );
+  $items['libraries_test/js_css/inline'] = array(
+    'title' => 'Test JavaScript and CSS: Inline code',
+    'page callback' => '_libraries_test_load',
+    'page arguments' => array('example_js_css', 'inline'),
+    'access callback' => TRUE,
+  );
+  $items['libraries_test/js_css/setting'] = array(
+    'title' => 'Test JavaScript and CSS: JavaScript settings',
+    'page callback' => '_libraries_test_load',
+    'page arguments' => array('example_js_css', 'setting'),
+    'access callback' => TRUE,
+  );
   return $items;
 }