Rating: 
Summary: A lot of fun, even if you don't get all the inside jokes.
Review: I enjoyed this book, but I suspect I would've enjoyed it more if I were more familiar with the Edgar Rice Burroughs Barsoom stories. Recursive SF is like alternate history in that you have to be familiar with the original material in order to get full enjoyment out of it. Also, this is not much like most of Niven's other work, so that may be a problem for some of those who prefer only "Hard" science fiction. That said, I recommend this book for a quick, entertaining read. It does help, as a previous reviewer stated, to read the short stories first. In fact, I think the book should've been printed in that order.
Rating: 
Summary: Disappointing
Review: I felt that the story telling was rather confused, and that the premise wasn't working at novel length. Note: I re-read the older Svezt stories first, which I recommend doing to facilitate following the story better.
Rating: 
Summary: Straight from Svetz report.
Review: I found myself having difficulty classifying this book. From its lingering descriptions of the bizarre things going on, I at first assumed that it was 'hard sci-fi' where the scientific speculation is more important than the plot. But the science is ludicrous! It's filled with the kind of hand-waving one sees in 'soft sci-fi' where the science is there only to further the plot, and need not be more than superficially plausible.So is the focus on the story? The story is passable but doesn't set your heart racing. The bottom line is that it doesn't take itself seriously either. What Niven seems to be going for is a conversion of fantasy and old science-fiction ideas to a modern science-fictional genre. It's an entertaining idea, but everything still ends up feeling like fantasy. He's made a few cosmetic changes, is all--what Orson Scott Card described as "science fiction has rivets, fantasy has trees." Rainbow Mars can't seem to do away with the trees.
Rating:
Summary: Hard or Soft Science?
Review: I found myself having difficulty classifying this book. From its lingering descriptions of the bizarre things going on, I at first assumed that it was 'hard sci-fi' where the scientific speculation is more important than the plot. But the science is ludicrous! It's filled with the kind of hand-waving one sees in 'soft sci-fi' where the science is there only to further the plot, and need not be more than superficially plausible. So is the focus on the story? The story is passable but doesn't set your heart racing. The bottom line is that it doesn't take itself seriously either. What Niven seems to be going for is a conversion of fantasy and old science-fiction ideas to a modern science-fictional genre. It's an entertaining idea, but everything still ends up feeling like fantasy. He's made a few cosmetic changes, is all--what Orson Scott Card described as "science fiction has rivets, fantasy has trees." Rainbow Mars can't seem to do away with the trees.
Rating: 
Summary: a waste of money....worse, a waste of time
Review: i found this book boring. it also went beyond my ability to suspend disbelief.
Rating:
Summary: Has he lost his touch?
Review: I found this book incredibly boring and difficult to follow, and I'm a huge LN fan. I do not recommend this to anyone.
Rating:
Summary: A most disappointing book!
Review: I hadn't read a science fiction book in several years, but decided to buy one when browsing a bookstore. I had always greatly enjoyed Larry Niven's novels and (especially) short stories, so I picked up this book. What an unfortunate choice! This book has few creative ideas. Since Niven is usually weak on characterization, this leaves little reason to read it. The references to some of the standard works on Mars are mildly interesting, but all-in-all, the book is dull and tedious. Very disappointing.
Rating: 
Summary: Over the Rainbow Mars
Review: I have always looked forward to Larry Nivens' works. As a master of "hard" science fiction Mr. Niven has few equals. Too bad this book is fantasy. I enjoyed the compilation of short stories previously published as "Flight of the Horse", now I realize why. They were short indulgences. A sideline to his normal, excellent SF. While long time SF readers will recognize the Martians encountered by Svetz and company during their "travels" to Mars' past, the book never develops past these recognitions. Entertaining to a degree but not what I look for from Larry Niven.
Rating:
Summary: Niven's disappointment.
Review: I have been a fan of Mr. Niven for many years and have found his work both technically plausible and readable. Rainbow Mars is neither. The inclusion of unicorns, dragons, and the borrowing of old SF plots set on Mars turn this into a "sword and sorcery" novel. The use of time travel was unconvincing, effectively no more than a "magic-wand" to link the story elements. This book was a major disappointment from an author I (formerly) expected to turn out high-quality science fiction.
Rating:
Summary: Surprisingly Bad
Review: I have never written to pan a book or record before but this book was so dissappointing, and the synopsis on the back of the book was so misleading that I felt I had no choice. I have read many great books by Larry Niven, and when I read the back cover I felt that I was in for another. What I got instead was an almost incoherent jumbled chaotic mess that barely had enough to it to limp to a two star rating. I found the fantasy intrusions to be particularly annoying. I didn't buy this book to read about Unicorns, Midgard Serpents, Rocs, Dragons, etc... As a matter of fact, had I even seen the word Unicorn on the back cover I would have dropped the book like so much nuclear waste. Not to mention the absurdity of the ridiculous "allied races" living on the Beanstalk (hangtree) Believe everything you have read, do not buy this book.
| 
