"At the dawn of the new atheist movement, the thinkers who became known as "the four horsemen," the heralds of religion's unravelling--Christopher Hitchens, Richard Dawkins, Sam Harris, and Daniel Dennett--sat down over cocktails for a filmed discussion. The video of the enthralling, path breaking evening that followed was released on YouTube and soon went viral. This is intellectual inquiry at its best: sincere and probing, funny and unpredictable, reminding us just how varied and colorful the threads of modern atheism are. Now, this landmark event is being published for the first time. The living participants, Dawkins, Harris, and Dennett, have all contributed new material to mark the evolution of their own thinking and highlight particularly resonant aspects of this epic exchange. Each of these men contends with the most fundamental questions of human existence as they challenge each other to articulate their own stance on god and religion, cultural criticism, spirituality without r