I’m not very good at writing book reviews, but I did want to recommend Robert Sawyer’s Neanderthal Parallax series:
Set in the present-time, this series explores the after-effects of a quantum computing event which joins together two alternate histories for planet Earth. In the one future, Homo Sapiens Sapiens was the surviving hominid species. In the other future, the Neanderthal survived and Homo Sapiens Sapiens went extinct. Building on some interesting premises based on the Neanderthal’s large nose and presumably acute sense of smell, the author creates a very compelling alternate reality. For example, fossil fuels are nowhere to be found on the Neanderthal world, and men and women lead mostly separate lives. There’s also some biting social commentary as the Neanderthals look at our world and find that we’ve really made a mess of the planet.
I still have to read the final book, but I can recommend the first two very highly.