Advances in graphics and computing power have given rise to a renaissance in virtual technologies from world-building platforms like Second Life to manufacturers of VR headsets like Oculus Rift. We're seeing more and more of human activity transfer to virtual spaces, offering people profound experiences via online personas and even transforming the way the real-world functions. Will we reach a tipping point where reality becomes a pale shadow of the rich, imaginative, virtual worlds we've created for ourselves? What will that mean for our perception of humanity? What do we risk losing?