Rendezvous with Rama by Arthur C. Clarke is one of the classic alien stories which is in large part defined by the fact that the aliens are never actually in the story directly. This makes it a disturbingly realistic feeling story. It does this in large part by never doing almost nothing that could not have been theoretically done at the time he wrote the story. There is no faster than light travel, no faster than light communication, no super weapons or anything else that isn’t potentially possible and some of the technology we have now has actually bypassed that of Rama.
The basic story of Rendezvous with Rama is set in the reasonably near future. Humans are living on a few different worlds in the solar system. Due to a few asteroid crashes humans have mapped all the bodies in the solar system very carefully and so find the odd one from out of the solar system early. This is Rama and it is soon discovered to be artificially made.
The only ship in range is sent out as quickly as possible taking the fuel from several other ships in order to do so. They are able to dock with the ship and begin to explore it. The ship is dead, but still well worth exploring. As they explore the ship it nears the sun and begins to change. Lights come on, water melts and eventually considerably more happens.
There are a couple of weaknesses, for me, in this story. The first of these is that there really is not all that much plot. The problem is there is no antagonist. This is effectively a disaster story, but without the disaster. A few minor things go wrong, but one of those is really dangerous at all. The other is that there is no real end to the story. This is a mystery without the solution given. This is, I assume because there are future books which explain much of this, but Clark is also not afraid to leave questions unanswered.
This is a very difficult book for me to rate because there is never a point in the story where I am bored, but on the other hand there are very few moments during the story when I feel much else either. Even the exhilaration of a new idea is uncommon because the ideas appear slowly and are often so based in reality, and have been used so often since that they do not feel new.
This is an extremely well written story with a brilliant idea at its core and while I might prefer a story with a bit more plot the exploration of a world has rarely if ever been done better. So if you want a story that explores what life in space might be like, how to travel between the stars and even how first contact with aliens is very likely to be then this is well worth reading.