Craig A. Boyd, A Shared Morality: A Narrative Defense of Natural Law Ethics. This is a very heavy philosophical work from St. Augustine to today, and it nuances every conceivable aspect of a theoretical ethic. Definitely not for the faint of heart. Its strength to me was the survey of so many modern views, but its weakness is how little it is based on Scripture. Boyd self-consciously tries to build an ethic on who man is rather than who God is. My position is that we can argue for biblical ethics without using the Bible but not without assuming the Bible and that our ethic must be based on who God is. Indeed, it is necessarily the case that all ethic is based on Him whether we recognize it or not.