diff --git a/google-isbn.cabal b/google-isbn.cabal
--- a/google-isbn.cabal
+++ b/google-isbn.cabal
@@ -2,10 +2,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 9c71c499b66014185b6b73de473fe9c0db1a158302c47c5391678c4aae9d872d
+-- hash: a0a62278f259457bfd73e5a721417ce3e6e5a49afbef73be562e9614e8846c23
 
 name:           google-isbn
-version:        1.0.2
+version:        1.0.3
 description:    Basic utility to search an ISBN using the Google Books webservice
 category:       Text, Web
 homepage:       https://github.com/apeyroux/google-isbn#readme
diff --git a/src/Google/ISBN.hs b/src/Google/ISBN.hs
--- a/src/Google/ISBN.hs
+++ b/src/Google/ISBN.hs
@@ -34,7 +34,7 @@
 
 data Book = Book {
   bookTitle :: T.Text
-  , bookSubtitle :: T.Text
+  , bookSubtitle :: Maybe T.Text
   , bookPublisher :: Maybe T.Text
   , bookDescription :: T.Text
   , bookPublishedDate :: T.Text
@@ -45,7 +45,7 @@
 instance FromJSON Book where
   parseJSON (Object v) = (v .: "volumeInfo") >>= \b -> Book
     <$> b .: "title"
-    <*> b .: "subtitle"
+    <*> b .:? "subtitle"
     <*> b .:? "publisher"
     <*> b .: "description"
     <*> b .: "publishedDate"