diff --git a/src/calibre/ebooks/metadata/library_thing.py b/src/calibre/ebooks/metadata/library_thing.py
index fdecf3fa99..8cc1282067 100644
--- a/src/calibre/ebooks/metadata/library_thing.py
+++ b/src/calibre/ebooks/metadata/library_thing.py
@@ -37,9 +37,14 @@ def cover_from_isbn(isbn, timeout=5.):
     if browser is None:
         browser = _browser()
     _timeout = socket.getdefaulttimeout()
-    socket.setdefaulttimeout(timeout)                
+    socket.setdefaulttimeout(timeout)
+    src = None                
     try:
         src = browser.open('http://www.librarything.com/isbn/'+isbn).read().decode('utf-8', 'replace')
+    except Exception, err:
+        if isinstance(getattr(err, 'args', [None])[0], socket.timeout):
+            raise LibraryThingError(_('LibraryThing.com timed out. Try again later.'))
+        raise
         s = BeautifulSoup(src)
         url = s.find('td', attrs={'class':'left'})
         if url is None: