Write SQL query to solve given problem: What is the name of the publisher that has published the most number of books?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT T2.publisher_name FROM book AS T1 INNER JOIN publisher AS T2 ON T1.publisher_id = T2.publisher_id GROUP BY T2.publisher_name ORDER BY COUNT(T1.book_id) DESC LIMIT 1