Quote Originally Posted by Weedhound
My three favorites:

The one Dutch Posted
The Cannabis Grow Bible by Greg Green
Marijuana Botany by Robert Connell Clarke

I second The Cannabis Grow Bible. I have read this from cover to cover many times, and even found it at B&N. I have a few books by Ed Rosenthal that are ancient but very helpful. My favorite book is one I made myself, by printing off every FAQ that pertained to my grow and every thread that had information I needed (such as WHs nute schedule). I sectioned this off in a binder and reference it all the time.

-Cheers-