I'm reading it now, but must return it to the library before I'm finished. I'm guessing you've finished it by now - what is your opinion overall? So far, I think he makes a good case for objectively determining the well-being of conscious creatures. He's saying that there is a moral truth b/c we can (in principle if not always in practice) say that there are ways of our knowing empirically what is good and what is bad, that morality's not relative in reality. That makes sense to me. Unfortunately many on the left have stupidly gone too far by suggesting that good and bad are determined by the culture one lives in, tolerating things that we can know are objectively bad for people even though their cultural hierarchy says it's good.
The last bastion of the religious is their claim to have an unquestioned ability to provide society with a set of impeccable morals. Sam Harris attempts to strip religions of this very last shred of legitimacy, one that traditionally scientists have ceded to them. He's trying to get ppl to start questioning this type of common wisdom that so many unthinkingly carry around about religion; that its got the exclusive rights to moral wisdom, and giving us a likely alternative. I believe he's right. Science has out-performed religion in every area of human knowledge and I think we will one day know that there are factual reasons for moral behaviour.
IMO, the book is worthy of a re-check. It's one of the best books I've read this year. He wasn't preaching to the choir in my case though. I strongly felt that morality WAS subjective, and entirely dependent on the culture or circumstances. Thanks to Harris, I am now of the opposite opinion. For me, there is nothing better than a book that offers a fresh perspective and trashes my previously held beliefs. This really was one of those "eureka" books.