We've all read scifi by brilliant minds with great technical ideas that somehow fell short in the storytelling department. And we've all read page-turners that gripped us, but didn't engage our minds.
But if we're lucky, we've also read Arthur C. Clarke.
"Rendezvous with Rama" is Clarke in peak form, combining great science with the kind of mysterious story that really sticks with you. The blend is perfect, and the pace of the revelations -- both scientific and dramatic -- is flawless.
In fact, the science and fiction in this science-fiction story are so amazingly good that the shallowness of the characters doesn't hurt the story. A cornerstone of scifi is looking at how people behave in situations that are out of the ordinary. Normally, that means that we need compelling characters with lots of development, layers, internal conflicts and bad hair days. The first time I read this novel, I was put off by the anonymity of the characters. Not only don't they have first names (perfectly reasonable, given that it's a military expedition), but there's very little about them that helps me identify with them. It wasn't until my second or third reading that I realized why that doesn't matter here: becuase the story and the science are so deep, I was *already* involved in the novel, and didn't need to get into a character's head to find my place in the story.
Sequels would do wonders for character development (though they were further examples of the dirty-old-man method of writing female characters), but wouldn't touch the sense of mystery, drama and even suspense that "Rendezvous" gave me. This isn't a library book; it's one you'll want to keep coming back to.