Some books we sell to local reefers are The Natural Reef Aquarium by Tullock and Aquarium Corals By Eric Borneman. Reef Invertibrates by Calfo and Fenner is a very good book also. I am getting three more books to read this week. I will let you know what I think after I read through them. They are Indo Pacific Coral Field Guide, Ultimate Marine Aquarium Book(I think it is just pictures and descriptions of hobbyist's reef tanks). And Reef Secrets.
A must have book set is Corals of the World by Veron. One of the best picture books I have ever seen.
Scott