This is hard SF published in 1972. The setting is near future 22. century, involving a 50km cylindrical BDO entering the solar system and its exploration by one crew. It won Hugo, Nebula, Locus and BSFA and several other awards and is considered as one of the most important works by Arthur C. Clarke.
The mysteriousness, curiousity, wide eyedness, sense of wonder and awe about the exploration is the center of this novel. It strifes to be as verisimal as possible – expect no FTL, here!
Clarke focuses on world building of the BDO Rama and strifes a little bit solar politics. The setting is most spectacular thing and I love the novel for it.
The story is optimistic and warm, it builds not very much tension but is at some points unexpected – especially at the end. There are no space fights or villains here!
On the downside, it has no character development at all and the characters should have a little bit more meat. That means one star less and leads me to 4 stars.