Denis Diderot was in more than one way a predecessor of Charles Gillispie, and this widely quoted passage does not, of course, apply only to knowledge about nature. It also describes how we acquire our understanding of history. Given the enormity of the world and the almost endless wealth of observations, it is beyond the reach of any single scholar to achieve anything close to a complete overview. Therefore, “profound reflection” and “exact experimentation” are all the more important. And so, we might add, are the organized and guided efforts of large communities of scholars and scientists working towards a common goal. Only then can we even approach collective “creative genius.”.