This introduces a new world. The immediate story is moderately well wrapped up but there is plenty of room in the world for more stories and some hint at the end that there might be more. OK, I'm (sort of) connected to the Internet, I got off my ass and looked it up; there is a second book in the series, In the Court of the Crimson Kings, 2008, which I don't think I've even seen.
This is an alternate universe which diverges from our own as we start to actually learn stuff about Mars and Venus. The early days of the space race were already different, but the world really changed when the Soviets landed a probe on Venus in 1962 and got video of what appeared to be humans until these Venusians smashed the camera. The story actually takes place in 1988 on a Venus shared by dinosaurs, Pleistocene megafauna, and stone-age humans. The major premise is a little hard to swallow, but the world extrapolated from it makes sense, and the accommodations the humans make to establish an Earth presence on Venus without miracle technology (so it's possible to get there but extremely hard and expensive) are fairly clever. Next to that, my standard complaint with alternate history (that once the alternate world has diverged, it should have quickly become much more different; even though things have changed a lot, they haven't changed enough), and some minor quibbles about the biology (if he's going to stress that the lower gravity and higher oxygen content allow bigger insects than earth, the insects should actually BE bigger than earth's -- but his dragonflies are only slightly bigger than what we have today, and a lot smaller than the ones we had back in the Carboniferous) are very minor. And, given how it touches me personally, I'm compelled to mention that adopting a baby predator from the wild only works that well in fiction, so please don't try it at home.
Every child of the 1970s wants to go play in a Land of the Lost that's not quite so hokey. International intrigue, heroic derring-do with dinosaurs and smilodons, a touch of romance -- it would be great for a movie, except that Hollywood would probably have to add Sleestak. We do get into some kinda-weird bigger picture stuff, but mostly this is just a big fun adventure. Not one for the ages, but a solid, fun read. 8 out of 10.
**** PLOT SUMMARY -- SPOILERS ****
It costs a brazillion dollars to send a man to Venus, and because it's been the center of Earth culture for a generation (Burroughs has made a big comeback), every kid wants to go, so Marc Vitrac is pretty proud of himself for being selected. He arrives on Venus, where he gets a ride on a dinosaur from the rocket to the base made of native materials. It's ruinously expensive to send humans, but even worse to send bulldozers, so the smart guys designed a control implant for the herbivores with pea-sized brains, which are used in place of engine-powered ground vehicles. Once Marc has learned some of the ropes, he accompanies a fossil hunting expedition, which provides further confirmation of the fossil record humans are piecing together, with life going from nothing to a copy of earth 200 million years ago in a geological instant. Other interesting stuff has been added to the ecology along the way, including ice age mammals, Neanderthals, and modern humans. They are caught in a flash flood, and Marc rescues a proto-canid pup colloquially known as a Greatwolf, which he tames into his Trusty Animal Companion. We start having a little friction between Marc and Chris Blair, the suspicious Brit, over the affections of Cynthia Whitlock, geologist. (Britain, it seems, attached itself to the US as an adjunct in the Space Race, and Blair seems to harbor some resentment. With Britain strongly tied to America in the worldwide competition against the Soviet Union, which is less warlike than in our history but still tense, the rest of western Europe is a backwater.)
Then a Russian shuttle crashes on the other side of the megacontinent. The Russians are worse positioned to attempt a rescue than the Americans, so they ask for help, and a dirigible Vepaja is sent, crewed by Capt. Tyler, Marc, Blair, Cynthia, Jadvika Binkis (wife of the pilot of the downed shuttle), and Tahyo the wolf. There are a couple of incidents of sabotage on the dirigible, where it looks to the reader like Blair has to be responsible, but everyone is considered suspect and he's not fingered specifically. Then they get caught in a hurricane. Tyler is severely injured and the ship badly damaged. Just when they seem to have patched her up enough to fly again, they're set upon by a pack of pterodactyls. The ship is destroyed and Tyler dies. On the good side, they're pretty much on top of where the shuttle went down when they get attacked by the Neanderthals with AK-47s.
At this point the action gets pretty furious. The local tribe of modern humans (the Cloud Mountain people) has been at war with the Neanderthals (Beastmen) for a generation. The Cloud Mountain folks are led by a princess who has a diadem which connects her with some sort of alien computer, but the Beastmen took over the cave with the computer and have been slaughtering the Cloud Mountain people. When the Russian shuttle landed, the Beastmen killed and ate two of the crew but took Binkis alive along with a bunch of AK-47s and the secret cargo of the shuttle. In the ensuing adventures, Marc teaches the Cloud Mountain people the secret of the bow and arrow, uses the dinosaur controller they managed to salvage from their airship (even though they had to blow everything else up to keep the Beastmen from taking it in a fight) to turn a triceratops into a tank, and leads the Cloud Mountain people to victory over the Beastmen. The computer in the cave apparently collapses the mountain on top of itself, but Jadviga and Binkis are transported somewhere else, where something disapproves of them and apparently kills them. Blair reveals that he's really a French agent (the French hope to sabotage the American, and also Russian, efforts enough to let them catch up in the space race, but he swears he had nothing to do with the Russian plot to drop a smallpox bomb on the Americans and the only native civilization more advanced than the stone age, which was the secret cargo. Marc marries the princess and leads her people across the continent to start a new life, since their old home was wiped out along with the basis of their culture.
The Sky People (which is the native's name for earth humans) now have to come to grips with compelling evidence that Venus is a zoo run by someone with magic-level technology. I'll have to see whether the series still has room to just be a good adventure, or if we have to face cosmic issues more directly, and if so how well it works, but I figure I'll read the next book when it wanders by.