Those who didn't have a misspent youth studying philosophy may be forgiven for not knowing what metaethics is.
It is one of the three main branches of moral philosophy alongside normative and applied ethics and, as Alexander Miller's excellent book makes clear, the best way to begin to understand metaethics is to contrast it with normative ethics - the debate about which actions are right and which are wrong, about what ought or ought not to be done and why.
Metaethics, on the other hand, is not concerned with making moral judgements but with considering what moral judgement is and what goes on when people engage in moral discourse and make moral decisions.
The great divide in metaethics is between cognitivists who hold that moral judgements express beliefs that can be true or false - "truth apt" - and non-cognitivists who hold that moral judgements express cognitive states like emotions and ideas and are therefore non truth-apt.
Beyond this relatively simple starting point, the whole debate becomes much more involved. But its complexities are masterfully handled by Miller and no student or teacher of the subject could want for a more knowledgeable and lucid guide.
In setting the agenda for his book Miller, in his unrelentingly precise and engaging manner, argues that contemporary metaethics is concerned with questions about meaning (what is the semantic function of moral discourse?), metaphysics (are there moral facts?), epistemology (is there moral knowledge?), phenomenology (how are moral qualities represented in a person's experience?), moral psychology (what is the motivational state of someone making a moral judgement?) and objectivity (can moral judgements be correct or incorrect - can we discover the moral truth?) This list, which Miller insists is not exhaustive, reveals the breadth of contemporary metaethics and the wide range of its concerns. It is certainly a list with sufficient variety to add new stimulus to the fascination with this intriguing, profound and ancient area of philosophy.
As Miller says, the list is much wider than many philosophers 40 or 50 years ago would have thought. Back then, he argues, philosophers tended to view metaethics as exclusively about language.
The great value of Miller's book to anyone seeking an in-depth knowledge of metaethics - and the reason why its first edition has been a core university text for a decade - is the confident and comprehensive grasp Miller has of the entire range of contemporary metaethical issues.
He is able to summarise and evaluate the cutting edge of metaethics so well because he himself is on that cutting edge, constantly engaging though papers, conferences and seminars with the world's leading metaethicists.
Very much a contemporary philosopher, he is contributing to and continually shaping the ongoing debate, not only in metaethics but in the philosophy of language as well.
So it is not surprising that he should keep his book truly contemporary by significantly updating it in the form of this superb second edition, which is essential reading for any moral philosopher who wants to be taken seriously.