Present or past tense?

Uusally, especially if you're writing a paper, you should refer to the book like it is happening at this very moment. It was his best book, I can agree with because he is definitely not going to writing any more, but the "It was about..." is formally incorrect. Ironic, hmm? A grammar book using incorrect grammar... Also, the use of "it" is annoying because "it" is an indefinite pronoun. But that's just me being picky...