Count the number of books written by Orson Scott Card.
"Orson Scott Card" is the author_name
SELECT COUNT(*) FROM book AS T1 INNER JOIN book_author AS T2 ON T1.book_id = T2.book_id INNER JOIN author AS T3 ON T3.author_id = T2.author_id WHERE T3.author_name = 'Orson Scott Card'