A Mountain of Madness in space, probably one of the finest First Contact story of all time, whose influence is readily visible in most of pop culture sci fi. Though never evasive in details Rendezvous with Rama is a big scientific tease, that does not deliver. At least not everything in the first book of a long series. 
 A near future Earth with interstellar travel, where scientists have exhausted almost every pantheon except the Hindu Gods in naming celestial bodies, intercepts a huge alien starship for asteroid somewhere outside the orbit of Jupiter and names it Rama. Then follows the chronic rendezvous by a manned survey vessel which investigates the alien world through its course till perihelion.Every single time they mentioned space drive, I was imagining Infinity Probability Drive and Heart of Gold, thank you Douglas Adams. 
 I couldn't help but compare it with Lovecraft's A Mountain of Madness all through the read, though one links to Ancient Astronauts and other to Future ones - Shoggoths in hollow earth and Ramans in an enormous steam cake hollow cylindrical ship. Loved the scientific explanations with the Raman ship, astronaut maundering, thrilling discoveries and detailed descriptions of an alien universe. Also it was quite cool to have it written from two aspects, from the pov of investigation crew and dissection by diplomats at space guard. That forgettable sequel of Independence Day totally stole the Space guard idea, though it didn't help them in any way. 
 Pretty sure, Rama's circular ocean was the inspiration for Interstellar's Cooper Station. And it would be amazing to see the whole world unravel in big screen, high time too. But there were issues in execution, atleast to me as a reader. The initial exploration and deductions off that gigantic space ship was totally contradicting with whatever got revealed by the end. Might make sense in further installments, still it leaves a sense of in-completion. And maybe, that is the point of whole thing.