diff --git includes/common.inc includes/common.inc
index 257542e..00ab385 100644
--- includes/common.inc
+++ includes/common.inc
@@ -4647,7 +4647,7 @@ function drupal_cron_cleanup() {
 
 /**
  * Returns information about system object files (modules, themes, etc.).
- * 
+ *
  * This function is used to find all or some system object files (module files,
  * theme files, etc.) that exist on the site. It searches in several locations,
  * depending on what type of object you are looking for. For instance, if you
@@ -6605,6 +6605,32 @@ function entity_uri($entity_type, $entity) {
   return $entity->uri ? $entity->uri : NULL;
 }
 
+
+/**
+ * Returns the label of an entity.
+ *
+ * @param $entity_type
+ *   The entity type; e.g. 'node' or 'user'.
+ * @param $entity
+ *   The entity for which to generate a path.
+ *
+ * @return
+ *   A string with the entity label (e.g. node title), or FALSE if not found.
+ */
+function entity_label($entity_type, $entity) {
+  $label = FALSE;
+  $info = entity_get_info($entity_type);
+  if (isset($info['label callback']) && function_exists($info['label callback'])) {
+    $label = $info['label callback']($entity);
+  }
+  elseif (!empty($info['entity keys']['label']) && isset($entity->{$info['entity keys']['label']})) {
+    $label = $entity->{$info['entity keys']['label']};
+  }
+
+  return $label;
+}
+
+
 /**
  * Invokes entity insert/update hooks.
  *
diff --git modules/comment/comment.module modules/comment/comment.module
index bda5f6d..af25f13 100644
--- modules/comment/comment.module
+++ modules/comment/comment.module
@@ -103,6 +103,7 @@ function comment_entity_info() {
       'entity keys' => array(
         'id' => 'cid',
         'bundle' => 'node_type',
+        'label' => 'subject',
       ),
       'bundles' => array(),
       'view modes' => array(
diff --git modules/node/node.module modules/node/node.module
index 9ab2454..b8207d1 100644
--- modules/node/node.module
+++ modules/node/node.module
@@ -181,6 +181,7 @@ function node_entity_info() {
         'id' => 'nid',
         'revision' => 'vid',
         'bundle' => 'type',
+        'label' => 'title',
       ),
       'bundle keys' => array(
         'bundle' => 'type',
diff --git modules/system/system.api.php modules/system/system.api.php
index a4d3510..ee49187 100644
--- modules/system/system.api.php
+++ modules/system/system.api.php
@@ -90,6 +90,9 @@ function hook_hook_info_alter(&$hooks) {
  *   - uri callback: A function taking an entity as argument and returning the
  *     uri elements of the entity, e.g. 'path' and 'options'. The actual entity
  *     uri can be constructed by passing these elements to url().
+ *   - label callback: Optional; A function taking an entity as argument and
+ *     returning the label of the entity, e.g. the title of a node, or the
+ *     subject of a comment.
  *   - fieldable: Set to TRUE if you want your entity type to be fieldable.
  *   - entity keys: An array describing how the Field API can extract the
  *     information it needs from the objects of the type. Elements:
@@ -106,6 +109,11 @@ function hook_hook_info_alter(&$hooks) {
  *       omitted if this entity type exposes a single bundle (all entities have
  *       the same collection of fields). The name of this single bundle will be
  *       the same as the entity type.
+ *     - label: The name of the property that contains the entity label. For
+ *       example, the value of this property in the node entity will be 'title'.
+ *       Note that it is possible that an entity label is a result of more
+ *       complex logic, in such a case the "label callback" should be used.
+ *       see entity_label().
  *   - bundle keys: An array describing how the Field API can extract the
  *     information it needs from the bundle objects for this type (e.g
  *     $vocabulary objects for terms; not applicable for nodes). This entry can
diff --git modules/system/system.module modules/system/system.module
index 8182427..01d8fc3 100644
--- modules/system/system.module
+++ modules/system/system.module
@@ -263,6 +263,7 @@ function system_entity_info() {
       'base table' => 'file_managed',
       'entity keys' => array(
         'id' => 'fid',
+        'label' => 'filename',
       ),
       'static cache' => FALSE,
     ),
diff --git modules/taxonomy/taxonomy.module modules/taxonomy/taxonomy.module
index a2a0ce0..3729d46 100644
--- modules/taxonomy/taxonomy.module
+++ modules/taxonomy/taxonomy.module
@@ -92,6 +92,7 @@ function taxonomy_entity_info() {
       'entity keys' => array(
         'id' => 'tid',
         'bundle' => 'vocabulary_machine_name',
+        'label' => 'name',
       ),
       'bundle keys' => array(
         'bundle' => 'machine_name',
@@ -122,6 +123,7 @@ function taxonomy_entity_info() {
     'base table' => 'taxonomy_vocabulary',
     'entity keys' => array(
       'id' => 'vid',
+      'label' => 'name',
     ),
     'fieldable' => FALSE,
   );
diff --git modules/user/user.module modules/user/user.module
index ea934cc..1fb9f6d 100644
--- modules/user/user.module
+++ modules/user/user.module
@@ -133,6 +133,7 @@ function user_entity_info() {
       'fieldable' => TRUE,
       'entity keys' => array(
         'id' => 'uid',
+        'label' => 'name',
       ),
       'bundles' => array(
         'user' => array(