This book is something new on Ethics and this is one of the reasons why I gave it 5 stars.
This is not a total beginner's book. You need some background on Cognitive Sciences and both Normative Ethics and Meta-Ethics. Often Mikhail is highly technical and he can use an entire chapter to cover a relatively unimportant issue. I think Mikhail is too generous to Rawls and attribute to him most of his own greater insights. So, ironically, you don't need much previous knowledge on Ralws' Theory of justice. Some basic understanding on Chomsky's ideas will help, but Mikhail will provide you with most you will need.
Mikhail proposal can be oversimplified by the following points:
1) There are some genetic encodings on our moral cognitions that should be common to all normal people regardless its cultural background.
2) The basic process created by this genetic encoding can be described on a similar way that of a Formal Grammar or any other cognitive process.
3) You can do Empirical research to uncover those invariant moral processes. This should be done by vanilla scientific method: you do some hypotheses and test those hypotheses against empirical data.
4) You have prima facie reason to believe that those processes have Normative force.
But prepare yourself to a MUCH deeper and nuanced analysis of those issues. And Mikhail will provide you with both reliable empirical data from the famous Trolley problems and a convincing cognitive model that match those data. And surprise: the heart of his model (the principle of double effect) has being around at least since Aquinas. Even so, Mikhail version is a master piece of precision.
I think Mikhail is basically the single guy pointing on the right direction while so many are talking no sense. Personally, I only have two critics on him (both unfair, if you take in account his relatively modest program):
a) The idea that our cognitive process can be modeled with some equivalent of a Turing machine is, on my view, wrong. It is true that this is the mainstream view. And even if it is wrong it still provides us with the best cognitive models available. But my own view is that the mind is a non-computable, pattern processor function. This objection is really only important to me, but the urge to adopt a mainstream model make Mikhail unnecessary attached with the Grammar analogy. He restricts himself with ONE kind of cognitive model. This model fits his first set of data, but he must grow past it if he wants his research program to takeoff.
b) His model does not make provision to structural aspects of ethics. I think not everything is genetically encoded and some ethical issues just can't be solved by firmware programmed to deal with hunter-collectors societies. Other that test if a cultural aspect is compatible with our basic wiring, his research program will not provide us with a model to judge the normativity of rules on complex social issues. But I have a intuition that he would answer to this with a: first things first. We first deal with the simpler issues, then we complicate them.
If you want to think Ethics on a different way, this book is for you. But if you hold hard to ideas like Cultural Relativist or Utilitarianism, you will find plenty of reasons to hate the guy that will show how outdated are those ideas.