+        book = get_object_or_404(Book, slug=slug)
+        if not book.gallery:
+            raise Http404
+        return book
+
+    def breadcrumbs(self):
+        return [
+            (_('books'), reverse('catalogue_document_list')),
+            (self.object.title, self.object.get_absolute_url()),
+            (_('scan gallery'),),
+        ]