Here is the tables relationships
SELECT book_title, subject_name
FROM Book
INNER JOIN Book_Author ON Book.book_ISBN = Book_Author.book_ISBN
INNER JOIN Author ON Book_Author.author_ID = Author.author_ID
INNER JOIN Subject ON Subject.subject_ID = Book.subject_ID
WHERE author_lastname = [whatever];
Edit to match the exact need:
SELECT book_title, subject_name
FROM Book
INNER JOIN Book_Author ON Book.book_ISBN = Book_Author.book_ISBN
INNER JOIN Subject ON Subject.subject_ID = Book.subject_ID
WHERE author_ID = '11';