What is your...

[markr]

Miniature Orchids is a great book, one of my favourites too. Home Orchid Growing by the same author is pretty comprehensive, a bit expensive, but probably the book I reach for the most.

Botanica's Pocket Orchids is a nice book if you want something with a little bit about lots of different orchids. Doesn't go into much depth but basic info for over a thousand orchid species.

My favourite book devoted to a specific type of orchid is Angraecoid Orchids by Joyce Stewart, Hermans, and Campbell. Again I'd prefer more detailed cultural information but lots of great pictures and basic scientific descriptions, plus a really nice intro chapter.