Nemesis was published in 1989, just three years before Isaac Asimov died. Of his later novels that I have read this is one of the better ones. This isn't to say that I liked it that much. It contains some ideas (Gaia, intelligent planets) that don't particularly appeal to me, but were prevalent in many of Asimov's works of this period. A decent, and short, summary is available from the link so I won't bother with one here.

Worth reading but not one of Asimov's better works.