A good treatment of fey that are closer to folklore than to standard D&D monster fare. There are a total of seven beings described (one of them with two variants), each fairly well written and including adventure ideas. CRs range from 2 to 18, although there is one special case somewhat debatably given a CR of 0.
The creatures have an interesting flavour, and are genuinely atmospheric. The book rounds out with a rather vague section on curses, some rules for fey marriage to mortals, and a selection of new feats. On the downside, the book has no artwork (other than the cover) and only a basic layout, so don't expect any frills.
Nothing outstanding, but not bad for the price, and the atmospheric nature of the beings elevates it to 4/5 from me.