G'day Mike (and others).
I realize that you are looking for opinions on orchid books for general culture, so (at the moment) these two invaluable orchid books are not what you are after.
But I must list them as two of the ''best available orchid books on the market now.''
The Genus Cymbidium by David Du Puy and Phillip Cribb
also
Masdevallias Gems Of The Orchid World by Mary E Gerritsen and Ron Parsons