As much as I am enamored of this book and its author, I feel a need to throw some "editorial finger-wagging" in at this point. I was feeling, about 2/3rds of the way through reading this, that it really wasn't "hanging together" as a book, and was wondering why the assorted sections varied so much in tone and structure. It was only after getting through the book (and its extensive footnotes) that I hit the "Acknowledgements" pages and found that this was, in large part, based on a handful of academic papers that Harris had published in his "day job" in Neuroscience, and especially in regards to research he's worked on in "neuroimaging" brain states. This was an "Aha!" moment, as some of the parts of this run towards the very technical, and are rife with footnotes pointing to research papers that, frankly, no one is likely to have much interest (unless they too were neuroscientists) in following up. An "About This Book" page up front (before the chapter-length Introduction) that set out that parts of this were from various research studies, and parts of it were "weaving this all together", would have made the subsequent "unevenness" of the book both understandable and expected (rather than my initial response that "gee, he doesn't do so well at writing long-form, does he?").
The book is broken up into six sections, an over-view introduction on "The Moral Landscape" which takes a look at various historical contexts of morality, then chapters on "Moral Truth", "Good and Evil", "Belief", "Religion", and "The Future of Happiness". These vary on how dependent they are on the scientific background, and how much "philosophy" (there's a 2.5 page footnote just dealing with Catholic pedophilia in "Moral Truth" section that is a fascinating read on its own) there is at core.
Generally speaking, Harris makes a case of there being a base-line for morality, linked to the concept of "well-being" of conscious creatures. While this has variable levels (what of whales, dolphins, chimps, dogs, cats, pigs?) which can be argued, the question of what provides the most well-being to humanity seems to be the central concern. Here is as close, I think, as he comes to an over-all statement (from the "Good and Evil" chapter):
To a large extent, the book expounds on this basic concept, of what does or does not promote well-being. Of course, this being Sam Harris, he gleefully takes numerous broadsides at the ludicrous aspects of religions and those who believe in them, and these are, naturally, some of my favorite parts (it is only with great restraint that I'm not quoting large blocks of rather florid text aimed at the Catholic church, or the far more pointed bits given over to the viler aspects of Islam).I believe that we will increasingly understand good and evil, right and wrong, in scientific terms, because moral concerns translate into facts about how our thoughts and behaviors affect the well-being of conscious creatures like ourselves. If there are facts to be known about the well-being of such creatures - and there are - then there must be right and wrong answers to moral questions. Students of philosophy will notice that this commits me to some form of moral realism (vis. moral claims can really be true or false) and some form of consequentialism (vis. the rightness of an act depends on how it impacts the well-being of conscious creatures). While moral realism and consequentialism have both come under pressure in philosophical circles, they have the virtue of corresponding to many of our intuitions about how the world works.
Here is my (consequentialist) starting point: all questions of value (right and wrong, good and evil, etc.) depend upon the possibility of experiencing such value. Without potential consequences at the level of experience - happiness, suffering, joy, despair, etc. - all talk of value is empty. Therefore, to say that an act is morally necessary, or evil, or blameless, is to make (tacit) claims about its consequences and in the lives of conscious creatures (whether actual or potential). I am unaware of any interesting exception to this rule. Needless to say, if one is worried about pleasing God or His angels, this assumes that such invisible entities are conscious (in some sense) and cognizant of human behavior. It also generally assumes that it is possible to suffer their wrath or enjoy their approval, either in this world or the world to come. Even with religion, therefore, consequences and conscious states remain the foundation of all values.
As one might expect from Harris' scientific background, there are fascinating parts here of the functioning of the human brain in relation to assorted "moral" input, from classic behavior experiments to his own work with scanning equipment to see what is active at what point given what conditions. Aside from his own research, he encapsulates a great deal of other material here, from that which questions "conscious" acts (where the body begins an action well before the mind "decides" to take that action), to differences in behaviors in various cultural categories. He also takes a few shots at other scientists who seem to attempt to bend over backwards to "play nice" with religion, or to justify faith-based stances, and tears up their arguments with aplomb.
I rather enjoyed The Moral Landscape and would recommend it to anybody with an interest in "how we work", as it is quite a look "under the hood" as it were, both from the philosophical perspective and the hard data of brain scan sciences. This has only been out about a half a year, so the "used" guys don't have deals at this point, but the hardcover is currently available for 40% off, and the paperback can be had for under ten bucks. It's certainly not for everybody, but it's a fun and interesting read.