While it was nice to get some background on the monsters, and the mythology, of the show, there were some fairly big flaws. For example, they say that Azazel - yellow eyes - is the demon they're looking for, they don't know who he is, but he can only be held by the Sigil of Azazel. Why are they ...
This was the first Supernatural(tv show) related book I had ever read, having purchased it with another book based on the show, Supernatural: Bone Key(novel). It did take me a while to actually pick this one up, simply because I'd rather spend my time watching the show, even if I've seen the episode...