After all the hype, John Mullan gives his verdict on the book which has dominated this week, Harry Potter and the Half-Blood Prince; Joseph O'Connor, author of Star of the Sea, imagines a secret love affair for Irish playwright JM Synge; Steven Rose hails an important attack on the selfish gene; Caryl Phillips finds that ER Braithwaite's classic tale of a West Indian teacher in east London, To Sir With Love, still offers valuable lessons; Stuart Jeffries meets combative moral philosopher Peter Singer, while James Wood enjoys a remarkable fantasia on Fyodor Dostoevsky's time in Baden Baden. Read it here tomorrow.