Harris, who has trained both as a philosopher and a neuroscientist, argues against the popular notion that science can have little or nothing to say about morality. Necessarily, he confronts related ideas like moral questions having no objectively right answer and science and religion being "nonoverlapping magisteria". Basically, he says that all moral questions must relate to maximizing the wellbeing of conscious creatures, and that what increases or decreases a creature's wellbeing can be studied scientifically at the level of the brain.
I just started reading it. Even if I'm not yet sure that I'm going to be completely convinced of the claim that "science can determine human values," I'm finding Harris to be a very clear thinker, as well as an amusing writer.
If you want a taste of his ideas and style, you can watch his TED talk, "Science can answer moral questions."
http://www.youtube.com/watch?v=Hj9oB4zpHww
http://www.amazon.com/Moral-Landscape-Science-Determine-Valu... (It isn't available from Amazon until October 5; I bought my copy in a bookstore.)
The book discusses how science can be used to deal with questions on morality.