I just installed your plug in and everything is great except for a message that is beside the book cover when I preview it. It says:
Warning: Missing argument 2 for get_post_meta(), called in /homepages/13/d345682146/htdocs/wp-content/plugins/totally-booked/templates/loops/single_book.php on line 36 and defined in /homepages/13/d345682146/htdocs/wp-includes/post.php on line 1465
I'm not sure what I've done wrong or how to fix that. Any help would be great. Thanks!