It can't be easy to be writing the first tie-in novel for a series that has ended up with such... ahem... 'dedicated' fans as Supernatural, but this turned out to be a very readable book. For the casual viewer of Supernatural, the early chapters might come across as a bit continuity heavy as there are several references to events in the series but it does the job of placing the events in the book between the season 2 episodes "Crossroad Blues" and "Croatoan".
The story is set in New York, something far easier to accomplish in a novel that on a film set in Canada, and one of the fun things in the book was to see the roadtripping Winchesters' reaction to the Big Apple. For the most part, DeCandido's characterisation of Sam and Dean is reassuringly close to how they appear in the series, a detail that writers of tie-in novels too often seem to slip up on. The original characters introduced in the book, including some friends of Ash, don't detract from the focus on the Winchesters. The plot, based around the writing of Edgar Allan Poe (hence the title: Nevermore), is suitably macabre.
It's not literature, and there are a few places where it jars, but for the most part the book keeps close enough to the tone and feel of the series to be an enjoyable read.