Philosopher extraordinaire A.C. Grayling, first Master of London’s New College of the Humanities, is on tour discussing ideas from his most recent book -The God Argument; the Case Against Religion and For Humanism. He was recently in DC as part of a CFI event and Chris Mooney's Point of Inquiry conversation.
From these it is a short transition to the 2nd part of the book which is the argument for ethical Humanism as a way of living a good life given the belief that there are no supernatural beings. Without religious doctrine this ethics must therefore be drawn from human experience, a history of which he draws from classic Greco-Roman thinkers such as Democritus, Epicurus and Lucretius. These are well represented in his previous work The Good Book.
You can see a bit of Grayling's tone and generosity of spirit in a brief video introduction to this book at http://www.youtube.com/watch?v=HYx_rayG4ec
For a very good summary of Grayling lecturing at length on the book see: