Instruct: Classify Amazon reviews into positive or negative sentiment
Query: As a science fiction story, this is pretty good.

As a mystery/whodunnit, it is horrible. Many of the reviewers here have commented on how difficult it was to anticipate the ending; of COURSE it was difficult; that's becuase the ending made no sense; worse, there was a perfectly logical, elegant solution to the mystery that was completely ignored simply for the purpose of jamming in a deus ex machina that would tie in to some of Asimov's other stories. And worse yet, it would have been possible to use the elegant solution as a part of the deus ex machina, if he really HAD to have that tie-in, and it would have made perfect sense.I can't explain here what that "elegant solution" is without giving away the book's ending, an unpardonable crime when reviewing a mystery, but if you're curious (and have read the book) feel free to e-mail me and I'll let you know what I think.