“Who we are and how we got here” by David Reich (a genetics professor who is a big name in the field), is the story of the various migrations and interbreeding of ‘human-like’ and human peoples over the last 50,000 years (with some references going as far back as 300,000 years).

Books on evolutionary psychology might be relevant, simply because evolutionary psychology relies on what evidence we have about how human behaved in pre-history as part of its evidence set. For example, as I recall The Evolution of Human Sexuality had to rely on a lot of anthropological and archaeological research to develop its theory and draw conclusions.

Also, anthropology and archaeology research touch on what it was like to be human before writing. Although ethnographies are a bit out of favor and have some clear issues with observer bias, ethnographies of foragers are probably our best look at what it was like to be a human prior to civilization. Similarly archaeology gives us some insight into what humans were like before writing via the artifacts they left behind, and I think of it as akin to paleontology in that it uses what evidence left to us by the past to infer what it was like: it's not perfect, but it's all we got.