Although Rendezvous ends with a large Sequel Hook, Clarke never seriously intended to write a follow-up - in fact, the three belated sequels were not written by Clarke, but by a friend of his, Gentry Lee. While Rendezvous with Rama was a hard science fiction, the sequels fell squarely on the soft side, focusing mostly on societal conflicts amongst humans trapped aboard the vessel, which is a muti-species zoo. The second book is a turning point. Attention is still paid to the layout of the spaceship, and practical methods to traverse the miles long cylinder, which has artificial gravity unevenly distributed within it, to the timing and effects of the energy beams from the spires, and to the general exploration, including the capture of biots found aboard. Additionaly the humans themselves have some inventions in the form of robotic bio monitors and an autonomous robotic surgeon, RoSur. However, this is with a backdrop of a military-scientist conflict where a conspiracy to profiteer off the mission leads to an accidental death, and the social characters of the astronauts are frequently used to engineer and explain the successes and failures of the mission.
While the conflict in Rama II is driven both by the encounters of the humans and the spaceship (which function as encounters between the human ambitions and that of the aliens who designed it) and by the humans' motives and personality conflicts, the third book focuses mostly on the social aspects of the sci-fi future. E.g. of living with a small family on an alien vessel, and after the second book the science is largely overshadowed by commercial conspiracies, government corruption, and a general replay of the '70s-'80s eras in space, complete with space HIV, once convicts and everymen begin to board the vessel. The later two books provide plenty of Everyone Has Lots of Sex, also of the squicky kind, as deliberate incest fuels the third and the fourth has a romantic subplot being a main driver of the characters' actions. This also changes the nature of the setting to some degree, ratcheting it significantly farther to the cynical side and turning up the Used Future level.
The bright side is that, as the books wear on, the biology of new alien creatures becomes more and more apparent. Book 3 details in its last arc Richard's journey amongst the Myrmicats and Avians, and Book 4 provides an in depth study of one alien race, the Octospiders (whose society values order over free will, and are capable of genetic engineering), whose language becomes a main feature. This gives the society on Rama an exploratory, Xenofiction feel, of being lost in a new environment (even if the new species seem like communist Russia parallels). The Xenofiction gets a brief glimpse at the node, where we also see alien species colected elsewhere and not kept on the Rama vessels, with whom Nicole comunicates.
The books in the series are:
- Rendezvous with Rama
- Rama II by Gentry Lee
- The Garden of Rama by Gentry Lee
- Rama Revealed by Gentry Lee
A movie version of the first novel has been languishing in Development Hell for decades, with Denis Villeneuve being set to take a crack at it after filming the sequel to Dune: Part One. An adventure game adaptation was released in 1984, and another in 1996.
"Rendezvous with Rama" includes these tropes:
- Absurdly Long Stairway: The interior of the eponymous gigantic cylindrical spaceship has three extremely long ladders running down from the airlock on the cap, which turn into stairways with "thousands upon thousands" of steps before finally reaching the "plain" which is the interior of the hull. Getting down all of this the first time takes the protagonists three chapters. Justified in that it's almost certainly a triple-redundant emergency backup system to whatever smaller vehicles the Ramans normally used.
- Alien Geometries: There's a sense of this, the interior of Rama using cylindrical coordinates. 'Up' and 'down' are towards and away from its rotation axis. Gravity reducing to zero at the hub doesn't help.
- Apes in Space / Uplifted Animal: The superchimps.
- Author Vocabulary Calendar: Instead of just being "named" or "called" something, a lot of objects are "christened".
- Benevolent Architecture: Every function of Rama is fitted with safety systems, each with triple redundancy, and the "biots" that maintain it all are seemingly programmed to avoid interaction with obviously living creatures. The end result, whether or not the Ramans intended it, is that it's very easy for a different spacefaring culture to explore the vessel at relatively little risk. The sequels reveal that such explorers have settled such vessels multiple times.
- Big Dumb Object: Rama
- Centrifugal Gravity: How Rama creates gravity in its interior.
- Cool Starship: It's pretty darn big, too.
- Cow Tools: Almost every aspect of Rama is unexplained, from its broad purpose to the functionality of its particular mechanisms. The plain in the northern half is mostly barren, with interspersed "cities" of structures that vaguely resemble manufacturing plants, but with no apparent means of ingress, or of transporting materials between them. The exploratory crew have to break into one to learn more, finding a collection of crystalline pillars that seemingly contain templates for manufacturing various items.
- Crazy-Prepared: The Ramans and their triple-redundant... everything.
- Distracted by the Sexy: At one point Captain Norton mulls the effects of zero-gravity on female anatomy.
- Eldritch Starship: In the sequels at least, the Raman fleet starts edging into this territory.
- Failed Future Forecast:
- Chapter 38 begins with: "According to the history books - though no one could really believe it - there had been a time when the old United Nations had 172 members." At the end of 2010, The United Nations had 192 members.
- The first novel, and the first sequel (Rama II) both assume that the Soviet Union would still be alive and kicking centuries into the future, even making the term "cosmonaut" the universal word for space travelers. The following sequels, written after 1991, quickly remove the action from Earth and the politics aren't mentioned again.
- Famous, Famous, Fictional:...how Neptune, Pluto and Persephone had been discovered.
Rama needed the grandeur of Bach or Beethoven or Sibelius or Tuan Sun, not the trivia of popular entertainment.
- The Federation: The United Planets, which has seven members: Mercury, Earth, Luna, Mars, Ganymede, Titan, and Triton. The fact that half of these are moons, not planets, is Lampshaded in the story.
- Foreshadowing: In the first book, Rama has a stain in the middle of one side, where something evidently collided with it. In the climax, one faction rashly sends a missile to collide with Rama, targeting the middle of the side, where the circle sea makes the thinnest point of the hull.
- Future Food Is Artificial: It's mentioned in passing that in human society, farming is now merely a popular hobby.
- Generation Ships: It's speculated by the humans that Rama is a failed example of this. By the end of the novel, it's pretty clear it isn't, and the sequels further prove the point.
- Giant Wall of Watery Doom: A minor course-correction on Rama's part, coupled with its rotation, leads to a massive tidal wave being generated on the ship-girdling lake. Unfortunately, it happens while some of the human explorers are on the lake. It quickly and unsurprisingly turns out that the Ramans had anticipated this possibility and installed a series of wave-killing baffles.
- Harmless Electrocution: The ship's doctor survives a nasty jolt while dissecting one of the spider biots.
- If Jesus, Then Aliens: The members of the Fifth Church of Christ Cosmonaut, who believe Jesus was a Sufficiently Advanced Alien.
- Improvised Parachute: a character uses his shirt as a parachute. Justified since he's jumping in Rama's reduced gravity, and the main purpose of the 'chute is to ensure he hits water feet-first.
- Industrialized Mercury: Mercury is inhabited by a community of temperamental miners, Hermians, that plot to destroy the titular alien spacecraft.
- Inertial Dampening: The sequels deal with this, as Rama II's human passengers travel between stars.
- Insignificant Little Blue Planet: The Ramans prove to have absolutely no interest in Earth, or any other planet in the solar system. The sequels change this.
- Limited Destination Time: The Endeavour can't stay with Rama when it gets too close to the sun.
- Lost Technology: IN SPACE!!
- Male Gaze: A POV character gets to exhibit this, thanks in part to the humanity's failure to develop artificial gravity by the 22nd century:Some women, Commander Norton had decided long ago, should not be allowed aboard ship; weightlessness did things to their breasts that were too damn distracting. It was bad enough when they were motionless; but when they started to move, and sympathetic vibrations set in, it was more than any warm-blooded male should be asked to take.
- Mile-Long Ship: It's pretty darn cool, too.
- Mundane Dogmatic: The humans in the first novel work at this level; it's a major plot-point that physics and technology simply won't allow any ship but the Endeavour to reach Rama, and its safe time there is sharply limited. Though see below under Sufficiently Advanced Aliens.
- Noodle Incident: A throwaway one in that Captain Norton was unable to find out what happened to the first four Churches of Christ, Cosmonaut.
- No Such Thing as Space Jesus: The sequels more or less state that the Rama ship-system was built by God. The original novel features a character who is a member of a religion which believes Jesus was an alien.
- Not Evil, Just Misunderstood: The Avians are another alien species inhabiting the Rama spaceship. At first unhelpful and even hostile-seeming to the humans, Nicole and Richard get them to help carry them over the wide sea (in a net made of either sessile material or mana melons) after spending some time learning to communicate with them in a rudimentary way. As we learn more about Rama it becomes learn these are another sentient species like humans, kept as part of the Raman zoo.
- The octospiders (in book 3) appear as completely terrifying and antagonistic. Later we learn that they can be friendly, and have a technologically advanced society, plus empathy. But before that they kidnap a human and as of book 3, he has not gotten over whatever experiments they performed on him while he was captive. The characters still ally with the octospiders at times.
- Oh, Crap!: The expedition's reaction to the Giant Wall of Watery Doom.
- The Only One: Justified as Rama is moving so quickly through the solar system that the Endeavour is the only ship in the right place, and with enough delta-V, to catch up with it and land. In the sequels, humanity knows the second Rama is coming, and can send a specially-prepared expedition.
- Reactionless Drive: The explorers cannot determine just how the ship can accelerate given it does not appear to push on anything they can detect. They assume the six pillars at the rear end of the cylinder have something to do with it, but cannot confirm.
- Rule of Three: One of the few things that is revealed about the Ramans is their predilection for the number three. They also insist on giving all their technology triple redundancy features in case of failure.
- A hologram of what is presumed to be some sort of clothing glimpsed briefly near the end of the first book implies that Raman bodies may have trilateral symmetry like the "spider" biots.
- Sequel Hook: "The Ramans do everything in threes.".
- Unintentionally so, though, as stated by Clarke himself. The fact that the series ended up comprising four books seems to support that.
- Starfish Aliens: From the sequels, Octospiders, Avians, Myrmicats and the Sessile Net. The last three live in a symbiotic relationship.
- Starfish Language: The Octospiders again.
- A Storm Is Coming: Human scientists realize that the heat caused by Rama's approach to the sun is going to cause hurricanes inside Rama, forcing the Endeavour crew to evacuate back to their ship for a time.
- Sufficiently Advanced Aliens
- Rama is a huge starship that has traveled presumably for millions of years without showing any signs of wear or damage except for a large smear on one side where something evidently collided with it. It uses a Reactionless Drive to perform a gravity slingshot within the outer atmosphere of the Sun to gain speed and head off in the direction of the Greater Magellanic Cloud. All of this, according to human science, is utterly impossible.
- The Fifth Church of Christ, Cosmonaut, holds that Jesus was one of these.
- Time Abyss: Rama and its contents.
- Tripod Terror: The "spider" biots who start swarming around the interior of Rama. Though they prove to be harmless to humans, unless you cut into the power-battery while attempting to dissect one of their corpses.
- You Have Outlived Your Usefulness: The Octospiders do this to themselves in the sequels.