What is history anyway? Most people would say it's what happened in the past, but how far back does the past extend? To the first written sources? To what other forms of evidence reveal about pre-literate civilizations? What does that term mean--an empire, a nation, a city, a village, a family, a lonely hermit somewhere? Why stop with people: shouldn't history also comprise the environment in which they exist, and if so on what scale and how far back? And as long as we're headed in that direction, why stop with the earth and the solar system? Why not go all the way back to the Big Bang itself?