From the introduction: The fey have arguably had the least amount of material made for them over the course of D&D history. While fiends, dragons, the undead, and aberrations have all had numerous sourcebooks detailing them, it wasn't until 4th edition that we finally received a sourcebook for the fey. In 3.5 there were less than 10 fey that broke the CR 15 mark, and that's including Dragon magazine and Dungeon magazine entries. The fey have never been given distinct classifications, such as the difference between true dragons and their lesser kin or the delineation between demons and devils. It wasn't until 4th edition that we even got statistics for unique fey lords, and those were confined to the pages of Dragon magazine and Dungeon magazine (excluding, of course, the statistics given in 2nd edition's Monster Mythology to detail the various fey gods). In short, the fey have always been more than a little ignored.