This 1982 book (that consists of 55 chapters plus an epilog), by Sir Arthur C. Clarke (who "said for years that [a sequel] was clearly impossible"), is really a hybrid book since it attempts not only to be a sequel to his previous novel ("2001: A Space Odyssey," published in 1968) but also attempts to be a sequel to the 1968 movie (also called "2001: A Space Odyssey").
In this novel, a joint Russian-American space mission is sent to the planet Jupiter (on the spaceship called "Cosmonaut Alexei Leonov") to try and discover what happened to the previous American spaceship (called "Discovery") that was sent previously in 2001. As well, Leonov's crew is "to locate the alien artifact [also called the monolith] encountered by Discovery, and to investigate it to the maximum extent possible."
Because this book attempts to be a sequel to the previous novel and the 1968 movie, it appeals to four different types of readers:
(i) those who have not read the previous novel and have not seen the 1968 movie
(ii) those who have read the previous novel only
(iii) those who have seen the 1968 movie only and
(iv) those who have read the previous novel and have seen the 1968 movie (as I have).
Each of these four types of readers will probably rate this book as follows:
(1) Those who have not read the previous movie or have not seen the 1968 movie will enjoy this novel. Reading the previous novel or seeing the 1968 movie is not needed to understand this novel. There is good character interaction and there is both known and speculative space science throughout. (Examples of speculative science include the idea that gas giant planets such as Jupiter may have diamond cores and there may be aerial life forms in Jupiter's atmosphere.) There are excellent descriptions of Jupiter and its moons (especially of the moons Io and Europa). As well, this novel's climax (that occurs in chapter 52) is exciting and unexpected.
These readers will probably give the novel a 5 star rating.
(Note that these positive comments will apply to the other types of readers indicated below.)
(2) The reader who has read the previous novel only will notice some differences that interfere with the continuity from the previous novel. For example, Discovery is no longer orbiting one of planet Saturn's moons but is now orbiting one of Jupiter's moons. (No explanation for this is given.) Instead of the monolith being on one of Saturn's moons, it is now in orbit around one of Jupiter's moons. (Again, no explanation for this is given.) As well, the mystery and awe of the previous novel is replaced with the straightforwardness of this novel. Many of the questions left open in the previous novel are now answered.
These readers might give this novel 3 1/2 stars.
(3) Fans of the 1968 movie will have a stronger sense of continuity after reading this book than those who have only read the previous novel. However, they may not recognize some of the dialogue that was said to exist (since it appeared in the previous novel only.) The overwhelming mystery and awe of the movie is replaced with the straightforwardness of this novel. However, many of the questions left open in the movie are now answered.
These readers will perhaps give this novel 4 stars.
(4) Those who have read the previous novel and have seen the 1968 movie might be a bit confused since they have to contend with what has been said in (2) and (3) above. But with some reflection, they should be able to sort out this confusion.
Possible rating by these readers: 4 stars.
As mentioned in (1) above, there is quite a bit of true and speculative space science throughout this book. Thus, this book would have different appeal to yet two more types of readers:
(5) Those without space knowledge. Such readers, I believe, would find this novel fascinating.
These readers would probably give the novel 5 stars.
(6) Those with some space knowledge. These readers would also be intrigued with the novel especially the speculative space science. However, they would be very dissappointed with the novel's climax (in chapter 52). For this climax to occur, there would have to be sufficient mass (which there isn't). Further, if this does occur (and it does in the novel), the novel would have to abruptly end since the spaceships (Discovery and Leonov) and Jupiter's moons would be instantly incinerated.
Possible rating by these readers: 3 stars.
The average of the above six ratings is 4 stars.
Finally, there is the 1984 movie called "2010: The Year We Make Contact." It is a straightforward, traditional science fiction movie. You don't have to read this book to understand this movie.
In conclusion, this novel as Carl Sagan says is "a worthy successor to 2001." It appeals in different ways to different people.