There are so many books about orchids that it would take forever to list them all down. However, there are titles that come very highly recommended as well written, very informative, and enjoyable to both neophyte and veteran orchid growers.
These are our favorite Orchid books:
Orchids For Dummies
The Illustrated Encyclopedia of Orchids
If you know which specific aspect you want to read about, there are orchid book listings categorized according to genus, cultural information, editions, etc.