Atheist and physicist, of some sort. He appears a lot in conferences, debates, talks, etc, about religion and science, and has a few books out. Probably first came across him in Beyond Belief, and have subsequently seen plenty of him online, and recently (as of 2012) have gotten annoyed by him in a few lectures, so he's not my sort of atheist, although he's on the right team. He seems to me not to be a very deep thinker, actually. It comes through in his debates, interviews, and panel discussions. He doesn't argue persuasively, misses the deeper points, and often bitches about philosophers.