diff --git a/src/calibre/gui2/actions/catalog.py b/src/calibre/gui2/actions/catalog.py
index 6c8568e83a..a6c0877049 100644
--- a/src/calibre/gui2/actions/catalog.py
+++ b/src/calibre/gui2/actions/catalog.py
@@ -18,7 +18,8 @@ from calibre import sanitize_file_name_unicode
 class GenerateCatalogAction(InterfaceAction):
 
     name = 'Generate Catalog'
-    action_spec = (_('Create catalog'), 'catalog.png', 'Catalog builder', ())
+    action_spec = (_('Create catalog'), 'catalog.png',
+                   _('Create a catalog of the books in your calibre library in different formats'), ())
     dont_add_to = frozenset(['context-menu-device'])
 
     def genesis(self):
diff --git a/src/calibre/gui2/actions/convert.py b/src/calibre/gui2/actions/convert.py
index 3034c0de18..68415db748 100644
--- a/src/calibre/gui2/actions/convert.py
+++ b/src/calibre/gui2/actions/convert.py
@@ -19,7 +19,7 @@ from calibre.customize.ui import plugin_for_input_format
 class ConvertAction(InterfaceAction):
 
     name = 'Convert Books'
-    action_spec = (_('Convert books'), 'convert.png', None, _('C'))
+    action_spec = (_('Convert books'), 'convert.png', _('Convert books between different ebook formats'), _('C'))
     dont_add_to = frozenset(['context-menu-device'])
     action_type = 'current'
     action_add_menu = True
diff --git a/src/calibre/gui2/actions/delete.py b/src/calibre/gui2/actions/delete.py
index a3ffdf03a9..fb3efd36c0 100644
--- a/src/calibre/gui2/actions/delete.py
+++ b/src/calibre/gui2/actions/delete.py
@@ -83,7 +83,7 @@ class MultiDeleter(QObject): # {{{
 class DeleteAction(InterfaceAction):
 
     name = 'Remove Books'
-    action_spec = (_('Remove books'), 'trash.png', None, 'Del')
+    action_spec = (_('Remove books'), 'trash.png', _('Delete books'), 'Del')
     action_type = 'current'
     action_add_menu = True
     action_menu_clone_qaction = _('Remove selected books')
diff --git a/src/calibre/gui2/actions/device.py b/src/calibre/gui2/actions/device.py
index 0f97553dcb..09cadceb9c 100644
--- a/src/calibre/gui2/actions/device.py
+++ b/src/calibre/gui2/actions/device.py
@@ -177,7 +177,8 @@ class SendToDeviceAction(InterfaceAction):
 class ConnectShareAction(InterfaceAction):
 
     name = 'Connect Share'
-    action_spec = (_('Connect/share'), 'connect_share.png', None, None)
+    action_spec = (_('Connect/share'), 'connect_share.png',
+                   _('Share books using a web server or email. Connect to special devices, etc.'), None)
     popup_type = QToolButton.InstantPopup
 
     def genesis(self):
diff --git a/src/calibre/gui2/actions/edit_metadata.py b/src/calibre/gui2/actions/edit_metadata.py
index 0ef17a59ce..968e7a072e 100644
--- a/src/calibre/gui2/actions/edit_metadata.py
+++ b/src/calibre/gui2/actions/edit_metadata.py
@@ -23,7 +23,7 @@ from calibre.db.errors import NoSuchFormat
 class EditMetadataAction(InterfaceAction):
 
     name = 'Edit Metadata'
-    action_spec = (_('Edit metadata'), 'edit_input.png', None, _('E'))
+    action_spec = (_('Edit metadata'), 'edit_input.png', _('Change the title/author/cover etc. of various books'), _('E'))
     action_type = 'current'
     action_add_menu = True
 
diff --git a/src/calibre/gui2/actions/fetch_news.py b/src/calibre/gui2/actions/fetch_news.py
index f94dfbc88c..d80bfdffe7 100644
--- a/src/calibre/gui2/actions/fetch_news.py
+++ b/src/calibre/gui2/actions/fetch_news.py
@@ -16,7 +16,7 @@ from calibre.gui2.actions import InterfaceAction
 class FetchNewsAction(InterfaceAction):
 
     name = 'Fetch News'
-    action_spec = (_('Fetch news'), 'news.png', None, _('F'))
+    action_spec = (_('Fetch news'), 'news.png', _('Download news in ebook form from various websites all over the world'), _('F'))
 
     def location_selected(self, loc):
         enabled = loc == 'library'
diff --git a/src/calibre/gui2/actions/open.py b/src/calibre/gui2/actions/open.py
index fc78df5f33..bf8c8335bb 100644
--- a/src/calibre/gui2/actions/open.py
+++ b/src/calibre/gui2/actions/open.py
@@ -11,8 +11,8 @@ from calibre.gui2.actions import InterfaceAction
 class OpenFolderAction(InterfaceAction):
 
     name = 'Open Folder'
-    action_spec = (_('Open containing folder'), 'document_open.png', None,
-            _('O'))
+    action_spec = (_('Open containing folder'), 'document_open.png',
+                   _('Open the folder containing the current book\'s files'), _('O'))
     dont_add_to = frozenset(['context-menu-device'])
     action_type = 'current'
 
diff --git a/src/calibre/gui2/actions/plugin_updates.py b/src/calibre/gui2/actions/plugin_updates.py
index 6973e80d8a..0951249b57 100644
--- a/src/calibre/gui2/actions/plugin_updates.py
+++ b/src/calibre/gui2/actions/plugin_updates.py
@@ -15,7 +15,7 @@ from calibre.gui2.dialogs.plugin_updater import (PluginUpdaterDialog,
 class PluginUpdaterAction(InterfaceAction):
 
     name = 'Plugin Updater'
-    action_spec = (_('Plugin Updater'), None, None, ())
+    action_spec = (_('Plugin Updater'), None, _('Update any plugins you have installed in calibre'), ())
     action_type = 'current'
 
     def genesis(self):
diff --git a/src/calibre/gui2/actions/polish.py b/src/calibre/gui2/actions/polish.py
index 858ea04947..127749cc51 100644
--- a/src/calibre/gui2/actions/polish.py
+++ b/src/calibre/gui2/actions/polish.py
@@ -365,7 +365,8 @@ class Report(QDialog): # {{{
 class PolishAction(InterfaceAction):
 
     name = 'Polish Books'
-    action_spec = (_('Polish books'), 'polish.png', None, _('P'))
+    action_spec = (_('Polish books'), 'polish.png',
+                   _('Apply the shine of perfection to your books'), _('P'))
     dont_add_to = frozenset(['context-menu-device'])
     action_type = 'current'
     accepts_drops = True
diff --git a/src/calibre/gui2/actions/preferences.py b/src/calibre/gui2/actions/preferences.py
index bbb86b573e..b1e066f979 100644
--- a/src/calibre/gui2/actions/preferences.py
+++ b/src/calibre/gui2/actions/preferences.py
@@ -17,7 +17,7 @@ from calibre.constants import DEBUG, isosx
 class PreferencesAction(InterfaceAction):
 
     name = 'Preferences'
-    action_spec = (_('Preferences'), 'config.png', None, _('Ctrl+P'))
+    action_spec = (_('Preferences'), 'config.png', _('Configure calibre'), _('Ctrl+P'))
     action_add_menu = True
     action_menu_clone_qaction = _('Change calibre behavior')
 
diff --git a/src/calibre/gui2/actions/restart.py b/src/calibre/gui2/actions/restart.py
index 9bbabedbbf..19619e581f 100644
--- a/src/calibre/gui2/actions/restart.py
+++ b/src/calibre/gui2/actions/restart.py
@@ -11,7 +11,7 @@ from calibre.gui2.actions import InterfaceAction
 class RestartAction(InterfaceAction):
 
     name = 'Restart'
-    action_spec = (_('Restart'), None, None, _('Ctrl+R'))
+    action_spec = (_('Restart'), None, _('Restart calibre'), _('Ctrl+R'))
 
     def genesis(self):
         self.qaction.triggered.connect(self.restart)
diff --git a/src/calibre/gui2/actions/save_to_disk.py b/src/calibre/gui2/actions/save_to_disk.py
index d1e056b65a..10574aea29 100644
--- a/src/calibre/gui2/actions/save_to_disk.py
+++ b/src/calibre/gui2/actions/save_to_disk.py
@@ -17,7 +17,8 @@ from calibre.gui2.actions import InterfaceAction
 class SaveToDiskAction(InterfaceAction):
 
     name = "Save To Disk"
-    action_spec = (_('Save to disk'), 'save.png', None, _('S'))
+    action_spec = (_('Save to disk'), 'save.png',
+                   _('Export ebook files from the calibre library'), _('S'))
     action_type = 'current'
     action_add_menu = True
     action_menu_clone_qaction = True
diff --git a/src/calibre/gui2/actions/show_book_details.py b/src/calibre/gui2/actions/show_book_details.py
index 2ab1e19edd..83e570d7b6 100644
--- a/src/calibre/gui2/actions/show_book_details.py
+++ b/src/calibre/gui2/actions/show_book_details.py
@@ -13,8 +13,8 @@ from calibre.gui2 import error_dialog
 class ShowBookDetailsAction(InterfaceAction):
 
     name = 'Show Book Details'
-    action_spec = (_('Show book details'), 'dialog_information.png', None,
-            _('I'))
+    action_spec = (_('Show book details'), 'dialog_information.png',
+                   _('Show the detailed metadata for the current book in a separate window'), _('I'))
     dont_add_to = frozenset(['context-menu-device'])
     action_type = 'current'
 
diff --git a/src/calibre/gui2/actions/similar_books.py b/src/calibre/gui2/actions/similar_books.py
index 7e7c02ce0b..93cb631ef7 100644
--- a/src/calibre/gui2/actions/similar_books.py
+++ b/src/calibre/gui2/actions/similar_books.py
@@ -14,7 +14,7 @@ from calibre.gui2.actions import InterfaceAction
 class SimilarBooksAction(InterfaceAction):
 
     name = 'Similar Books'
-    action_spec = (_('Similar books...'), None, None, None)
+    action_spec = (_('Similar books...'), None, _('Show books similar to the current book'), None)
     popup_type = QToolButton.InstantPopup
     action_type = 'current'
     action_add_menu = True
diff --git a/src/calibre/gui2/actions/store.py b/src/calibre/gui2/actions/store.py
index b84836c465..896516c665 100644
--- a/src/calibre/gui2/actions/store.py
+++ b/src/calibre/gui2/actions/store.py
@@ -17,7 +17,7 @@ from calibre.gui2.dialogs.confirm_delete import confirm
 class StoreAction(InterfaceAction):
 
     name = 'Store'
-    action_spec = (_('Get books'), 'store.png', None, _('G'))
+    action_spec = (_('Get books'), 'store.png', _('Search dozens of online ebook retailers for the cheapest books'), _('G'))
     action_add_menu = True
     action_menu_clone_qaction = _('Search for ebooks')
 
diff --git a/src/calibre/gui2/actions/view.py b/src/calibre/gui2/actions/view.py
index fe7ef72986..55e07533c3 100644
--- a/src/calibre/gui2/actions/view.py
+++ b/src/calibre/gui2/actions/view.py
@@ -34,7 +34,7 @@ class HistoryAction(QAction):
 class ViewAction(InterfaceAction):
 
     name = 'View'
-    action_spec = (_('View'), 'view.png', None, _('V'))
+    action_spec = (_('View'), 'view.png', _('Read books'), _('V'))
     action_type = 'current'
     action_add_menu = True
     action_menu_clone_qaction = True
diff --git a/src/calibre/gui2/preferences/toolbar.py b/src/calibre/gui2/preferences/toolbar.py
index bae7a83e0b..8aa85af3d9 100644
--- a/src/calibre/gui2/preferences/toolbar.py
+++ b/src/calibre/gui2/preferences/toolbar.py
@@ -28,9 +28,10 @@ class BaseModel(QAbstractListModel):
 
     def name_to_action(self, name, gui):
         if name == 'Donate':
-            return FakeAction('Donate', _('Donate'), 'donate.png',
-                    dont_add_to=frozenset(['context-menu',
-                        'context-menu-device']))
+            return FakeAction(
+                'Donate', _('Donate'), 'donate.png', tooltip=
+                _('Donate to support the development of calibre'),
+                dont_add_to=frozenset(['context-menu', 'context-menu-device']))
         if name == 'Location Manager':
             return FakeAction('Location Manager', _('Location Manager'), 'reader.png',
                     _('Switch between library and device views'),
@@ -247,6 +248,18 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         self.remove_action_button.clicked.connect(self.remove_action)
         self.action_up_button.clicked.connect(partial(self.move, -1))
         self.action_down_button.clicked.connect(partial(self.move, 1))
+        self.all_actions.setMouseTracking(True)
+        self.current_actions.setMouseTracking(True)
+        self.all_actions.entered.connect(self.all_entered)
+        self.current_actions.entered.connect(self.current_entered)
+
+    def all_entered(self, index):
+        tt = self.all_actions.model().data(index, Qt.ToolTipRole).toString()
+        self.help_text.setText(tt)
+
+    def current_entered(self, index):
+       tt = self.current_actions.model().data(index, Qt.ToolTipRole).toString()
+       self.help_text.setText(tt)
 
     def what_changed(self, idx):
         key = unicode(self.what.itemData(idx).toString())
@@ -264,7 +277,7 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         names = self.all_actions.model().names(x)
         if names:
             not_added = self.current_actions.model().add(names)
-            ns = set([x.name for x in not_added])
+            ns = set([y.name for y in not_added])
             added = set(names) - ns
             self.all_actions.model().remove(x, added)
             if not_added:
@@ -283,7 +296,7 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         names = self.current_actions.model().names(x)
         if names:
             not_removed = self.current_actions.model().remove(x)
-            ns = set([x.name for x in not_removed])
+            ns = set([y.name for y in not_removed])
             removed = set(names) - ns
             self.all_actions.model().add(removed)
             if not_removed:
diff --git a/src/calibre/gui2/preferences/toolbar.ui b/src/calibre/gui2/preferences/toolbar.ui
index c8ff4977eb..2bb9547b3e 100644
--- a/src/calibre/gui2/preferences/toolbar.ui
+++ b/src/calibre/gui2/preferences/toolbar.ui
@@ -234,6 +234,13 @@
      </layout>
     </widget>
    </item>
+   <item>
+    <widget class="QLabel" name="help_text">
+     <property name="text">
+      <string/>
+     </property>
+    </widget>
+   </item>
    <item>
     <widget class="QWidget" name="spacer_widget" native="true">
      <layout class="QVBoxLayout" name="verticalLayout_5">