DaMaDo
Contributor
It is very good, but maybe a bit hard core for someone with less than 24 lifetime dives.Dive Manuals
Deco for Divers
The best single source for deco theory specifically written for scuba divers
I read Deco for Divers(amazon link) before I had 20 dives and I got a lot out of it. It's really interesting. I think even those who don't dive, but are interested in the physics and physiology of diving would really appreciate that book. It's a high quality print job too.
I also enjoyed Diver Down...lots of good recommendations in this thread, hopefully I can get some more dive reading done this semester.