Technology is all around us, expanding the limits of what is possible. but every once in a while, some invention or insight has an outsize effect; it creates a large dis­continuity, dividing history into “before” and “after.” The steam engine, the transistor, the World Wide Web—each of these ideas seemed to emerge from nowhere to change our world in fundamental ways. Which key technology will arise fromtoday’s vast cauldron of innovation to become tomorrow’s world changing idea? It’s impossible to know, of course, but we know it will come.