The Sky People by S. M. Stirling
In his acknowledgments, Stirling refers to the works of authors such as Edgar Rice Burroughs. This story of an Earth-like Venus presumably has something in common with those earlier works. Perhaps, I should preface my comments by noting I don't recall having read any of Burroughs’ Mars or Venus books. Even in my youth when I wasn't a nitpicker for scientific plausibility and such, stories of planets with green men living lives similar to Conan The Barbarian, The Three Musketeers, swashbuckling pirates or medieval-ish heroes and princesses weren't on my to-be-read list.
The Sky People certainly does not intend to represent reality in our universe. It was published in 2001. Yet, according to the story, both the US and the East [a Russian-Chinese alliance] have settlements on an essentially Earth-like Venus. The US hasn't fought a war since Korea. And other clear departures from our history.
Venus has an odd mix of Earth-like life - dinosaurs, saber-tooth tigers, cattle-like animals, Neanderthal-like hominids and Bronze Age Earth-like humans. Actually, the DNA of these animals suggests that more than parallel evolution is involved. And there is geological and fossil evidence indicating complex life and other Earth-like features began relatively recently (recently in geological terms, that is). So, there is a mystery here that might give a plausible view of a Venus in a parallel universe that took a different path than ours. But it’s not the Venus we know.
Aside from brief references to this DNA anomaly, for more than half the book the story is about Earth humans on a planet of "prehistoric animals" and native humans/hominids at a Stone Age or Bronze Age level. The Earthmen have a mix of modern technology and lower-tech solutions because of the expense of transporting equipment to Venus. Eventually, we begin to see suggestions of advanced tech. However, considering this book does not pretend to take place in our universe, and we are dealing with pre-scientific natives who believe in magic, when we first encounter something “indistinguishable from magic”, the reader may not first assume it is a "sufficiently advanced technology". So, the fantasy-like flavor of the book does not necessarily immediately disappear.
The beginning of the book provides the reader with an introduction to the presence of the Earth people on Venus and their conditions. The bulk of the book is an adventure with Earth people out in the wild dealing with the predator animals, with warring Neanderthals, and more complicated relations with the Bronze Age people. There’s an element that adds a more science fictional aspect later in the book, but to the extent this plays a significant role in the story – for the most part, the story could have followed the same course without it. The book’s ending suggests this science fictional element may play a greater role in the sequel. However, I would think the book will appeal most to readers who would be satisfied with a story that is strictly about space age Earthmen visiting a “prehistoric planet”.
It's written in an entertaining way. It wasn’t a bad book, but it didn’t satisfy what I look for in an SF novel.