This is one of the last of Isaac Asimov's solo novels, and I'm sorry to say it's not his best. It has his usual light-hearted, friendly style, but it lacks the spark of ingenuity that brought his Foundation and Robot stories to life. He's got a lot of the right elements in place - Eugenia, the troubled but brilliant teen; Eugenia, her talented but outmatched mother; Crile, the focused but malleable father; Janus, the colony's megalomanic director - but much of the dialogue and introspection seems more rote than inspired. Asimov, in a brief foreword, makes a point that he tries to write clearly rather than poetically, and he's always succeeded at that. This time, however, clarity isn't enough to carry the story.
As always with Asimov, the science is credible, though he stretches the point with Nemesis' local lifeform. Unfortunately, the science here also isn't particularly interesting. By 1989, there wasn't much new in any of these ideas, and Nemesis lacks the human element needed to keep it engaging
Asimov was one of the true greats of science fiction (and, based on his autobigraphy and author's notes, a genuinely nice person), but this is not one of his best books. It's an adequate but not gripping SF sorta-thriller that doesn't stand out, and isn't the best testament to an SF Grandmaster. Read it for completeness sake, but don't expect too much.