The closest thing to a definitive book on phalaenopsis is Christenson's "Phalaenopsis, a monograph".
http://www.amazon.com/exec/obidos/tg...24946?v=glance
There are some more elementary books like Mary Noble's " you can grow phalaenopsis" but I would suggest the Christenson book if you would like descriptions of all 60 or so species with photos and in depth information.