Humanino's thread reminded me of an old idea for a Sci Fi novel. What if we took all of our knowledge back in time, say to the earliest humans, and teach them what we know now; including all of science, history, medicine, economics, sociology etc. How would the world evolve. Where would we be today? What would history be like? Assume that we can only pass on our knowledge in the form of a few hundred solar powered palmtops. So, less this device, no hardware can be passed along. IIRC, I allowed seven people to remain in the past to teach.