Option Lock is what I describe a competent Book, which is serviceable on all circles. Really I don’t have anything to complain, and yet I’d rate it a 2.5, because frankly it’s very “Middling”. Don’t get me wrong, I thought the Book was solid, but sadly not one that really made me want to go and re-read it like some of the best EDAs did. And frankly it’s just a bit unremarkable.