If you write a book which ends in such an intriguing way as 2001, the nicest thing to do is to write a sequel. Thankfully, this is what happens on this book.
It's quite an enjoyable read, with very interesting passages such as the description of Europa's surface. Or what it is like to orbit Jupiter.
Characters are still quite weak, and human relationships are depicted in a beyond-simplistic way. Not quite surprising, though. But if you ignore it and focus on the rest, it's a very readable book.
The end is quite... unbelievable. But maybe possible. Who knows?