Instruct: Classify a review as either positive or negative.
Query: Demanding but brilliant novel

While not for everyone, I thought Time's Arrow was absolutely brilliant -- an admittedly unoriginal central idea (he credits Vonnegut's Slaughterhouse Five in the acknowledgements) is nonetheless played out perfectly. The moment in which the reader realizes why the man's soul has been viewing the life backwards -- so that the atrocities committed during the Holocaust would be bearable -- is one of the most stirring, chilling moments I've come across in fiction.