I think you need to decide on a topic or if you are looking for a reference guide. My best reference books are Taylors Guide to Orchids and Botanica's Orchids.
For learning, Northers's Orchids as House plants is good. And for me Steven A. Frowine has a book I use called Fragrant Orchids. If you join the AOS, they have a Your First Orchid Booklet and then there is John Tullocks Growing Hardy Orchids
