This sub is certainly the correct one for the prehistoric human past, and I'm a bit tired of having to justify my own specialisation (and that of an entire flair category) every time a prehistoric question comes up in the sub.

Anyway, there was a recent popular thread that asked a similar question. I can copypaste from my answer there:

Now, this does not mean that people back then were not 'civilised' or were 'backwards' or 'undeveloped'. Rather, they had developed a succesful lifestyle adapted to their circumstances. These include hunting big game, fishing, collecting wild plant resources etc. There was no need for grain storage, or for working together to irrigate cultivated fields. There was, apparantly, no need to develop all these things that you might call 'civilisation'. This nice circular argumentation makes clear that in our current understanding, there could not have been a 'lost civilisation' building cathedrals and writing books, because there is no evidence for that. There was, however, a rich world with its own music, culture, beliefs, and art that is now lost to us.

My list for further reading, divided by geographical region, is a bit further down here.

To elaborate a bit, all modern humans (and none of our non-human cousin species) share an ancestor that lived about 200.000 years ago in Eastern Africa. The earliest indications for fully modern human behaviour (like needles for clothworking, traps for hunting small animals, and fishing gear, among others) are also from around this time, with early examples from both South and North Africa. Until about 60.000 years ago, 'Africa' had its border roughly in the modern Levant, where our human ancestors would have been able to meet Neanderthals continuously. This area is quite vulnerable to climatic fluctuations, however, so it is not at all certain that we ever really met our cousins there, or whether we just happened to use the same area whenever the climate was most suitable for our respective ecological niches (so possibly no clan-of-the-cave-bear-type 'species wars').

Around the time when modern humans left Africa was the middle (but not the height) of the last Ice Age. This meant that large parts of the Eurasian land mass were exceptionally well suited for hunting large game. Lifestyles in this areas might have been a bit similar to the American Plains Indians before the introduction of the horse and firearms. It is only with the end of the Ice Age (and the extreme climatic fluctuations that came with it) that the development of agriculture took hold.

Rather than /r/askscience, I would suggest /r/asksocialscience. This falls under the study of biological anthropology, and there's more of them in that sub.