I already have a good draft of the manuscript, but I'll be putting in some more work to meet the publisher's formal requirements (house style, etc.), get it down to 45,000 words, and generally make sure I'm happy with it. If all goes well, expect to see the book published (primarily as an e-book, but with print on demand available) in about six months.
I'm excited, of course. Palgrave Pivot is a quality publisher - actually a specialist academic imprint of Palgrave Macmillan, which is part, in turn, of the large Macmillan Group. At the same time, a small book of this sort will enable me to set out my views on some fundamental issues in moral philosophy in a way that's concise and to the point, but still allows room to develop some detailed arguments.
I'll be attempting to do justice to a range of philosophical views, while criticising them. These will include some that are often dismissed quickly: my approach is to look at the strongest versions of, say, moral relativism, I can find, attempting to identify what their attraction might be and what grains of truth they might contain. Often I see writers attack vulgar or weak versions of philosophical theories that they dislike, which does little for intellectual progress (or even for conveying what serious theories are on offer).
The Mystery of Moral Authority will also serve as a manifesto for my own positive account of morality and moral philosophy. Don't expect me to spell that out here (if I could do so in a blog post, I wouldn't need to write a book!). Still, to give a hint of the direction, the manuscript currently states that moral error theorists are the closest thing to my "tribe" among proponents of various contemporary approaches to metaethics.