Non Spoiler Section:
This book is the third in the monolith series (2001/2010). It continues 50 years after the climactic and brilliant end of 2010. My problem with this book is that it is pointless and doesn't fit the series.
The story isn't overly coherent or seemingly complete, almost as if A.C.C had a 300 page limit and had to quickly wrap things up. The writing style is very different, much shorter chapters, every one with a little cliffhanger or reveal.
It has some great ideas, but that does not warrant this book. I have yet to read 3001, if it has good reviews then get this to complete the series, if not I'd stop at 2010.
Spoilers:
Ok, so what's wrong with it? Hal and Bowman turn up for approx 2 pages. Heywood has no real relation to the story, in fact his trip to the comet never recieves a pay off later on. His becoming immortal made little sense in terms of the how, the why or the when.
The plot involving Europa, while more interesting, is closer to a thriller than an adventure. There's little climax to it all, the rescue is glossed over in a few words, the 'diamond' revelation appears early on in the script. The USSA 'intrigue' is not resolved. It's poor storytelling.
In regards to moving on the series plot, the cliffhanger is AWFUL, it's a sloppy one line at the end that has no reference to events before or it's ramifacations. The monoliths don't actually do anything at all in this book.
This story, to me, would make far more sense as a stand alone book than a "2010" sequal.