To take a leap of faith is to bet your belief on an unknown future. But belief is central to the human experience whether it's religious, political, societal, philosophical or spiritual, the act of believing can be a lodestar, a comfort, a ritual, a guiding principle, a reason for living. We place our faith in everything from gods and mortals to medicine and magic, and while the bet doesn't always pay off, it can usually tell us something about our desires, our values and our selves. What's the role of religion in today's increasingly secular world? Why are we so obsessed with cults? How have the internet and social media attenuated (or, in some cases, enhanced) our ability to believe what we read?