They move forward to their future and find their world in worse shape than before. A farcical homage to classic SF Rainbow Mars varies markedly from the hard science fiction that readers have come to expect from Larry Niven. It is a confusing mix of farce and hard SF adventure that pays homage to the classic Martian adventures of H.G. Wells, Edgar Rice Burroughs, C.S. Lewis and others, expanded from a series of Niven's own short stories published in the late '60s and early '70s. That idea alone could form the nucleus of a good SF novel. But the narrative of Rainbow Mars is seldom compelling, and characterization is virtually nonexistent.
Details seem haphazardly chosen, without serious research or thought.
All of this combines to make Rainbow Mars a mixture that, unfortunately, never gels into a coherent whole. Niven has done much better in the past, and readers can only hope that he will do so again. I guess that even power hitters like Larry Niven can't hit home runs every time. They will irritate, provoke and make readers question certain cherished beliefs. A trio of stories are indicative of what is to be found here.