Fortunately they really know how to kick ass. In this book humanity is not much in advance of cavemen in term of technology, and most are still living the lives of nomadic tribes. That is very nice for them but they make the Homo sapiens seem rather shabby in comparison. A sentient one that walk upright, has developed language, culture, social organization and science. No, the Yilanè are a species of dinosaur. It is would not be accurate to say they are descended from dinosaurs as these creatures are still around in the universe of this book. What the above quote does not state clearly though is that the Yilanè are dinosaur people!. OK, that saves me at least 45 minutes of trying to think of a coherent description. The intelligent reptiloid species is called the Yilanè.” Consequently, the Cretaceous–Paleogene extinction event which wiped out the dinosaurs and other reptiles never happened, leaving the way clear for an intelligent species to eventually evolve from mosasaurs, a family of Late Cretaceous marine lizards closely related to the modern monitor lizards.

“In the parallel universe of this novel, Earth was not struck by an asteroid 65 million years before the present. The following paragraph is lifted entirely from Wikipedia: So whether you choose to go east or west of Eden you would be on to a very good thing in either direction. John Steinbeck's East of Eden is one of my all-time favorite novels, the late great Harry Harrison’s West of Eden is another one.

Harry harrison eden