This product is a Monster Manual style book that focuses fey creatures drawn from various legends, including Jack In Irons, Dullahans, Erlking, and other creatures you can actually input into a Wikipedia search and learn some interesting stuff about. The mechanics in the book offer solid baseline 4e entertainment, there's nothing in it that will cause one's eyes to burst with its inventiveness, but at the same time nothing broken or unreasonable. The iconic monster, Jack In Irons, is a campaign-ending Solo creature in the ranks of monsters like Orcus and Demogorgon. There are a variety of other creatures for multiple levels. I would put this book at around Monster Manual 2's level of quality, with a lot of useful monsters of which you can be sure none will be too tedious to use (unlike, say, Wraiths). The layout is serviceable and the artwork is pretty good. If you need more Fey monsters, you'd likely enjoy this book. You certainly will find it hard to beat the price tag. If it had been a bit bolder with its mechanics it would have earned a five star score, but in 4e it is perhaps better to keep the rules tried and true.
[4 of 5 Stars!]