Rainbow Mars features the continuing adventurers of the time traveller Svetz, who first appeared in the short story collection "Flight of the Horse". If you are lucky (depending upon your geographical location) you will get a free copy of these stories in the same volume as Rainbow Mars.
Its good to see that Niven can still write in the old style - the plot of this story allows a prime opportunity for him to "play tourist" again.
The premise of the story is back to the Institue of Temporal Research to gain yet another prize exibit for Waldemar the Eleventh. This time the Secretary General wants a captive Percival Lowell Martian who created the Canals on Mars that mysteriously disappeared before the space age probes visited the planet. An exploratory mission is sent via a series of extension cages and landers and roving rovers. This mission detects a flourishing civilisation made up of many sentient species. Also discovered is a huge orbit-spanning tree or beanstalk.
On seeing this woody wonder Waldemar the Eleventh immediately orders a manned mission to Mars to collect seeds from this tree to enable a space elevator to be grown on Earth. Svetz and two female astronauts from the Space Bureau accompany him. (for Rishathra fans the fist instance of sex occurs on page 29!). The overwhelming success of their mission has dire consequences for the future of Earth.
This report prepared by Nesssus