I'm relearning how to read. At university one of the first things our Philosophy lecturer taught us was to how to read. You gotta break stuff down, look at it critically, find the tender spots, grind it down with your teeth and chew the marrow out. You can't just sit there and expect the stuff to flow into your brain.
This book, the Fundamentals of Database Systems, is as far as I can tell, the definitive book on database theory and practice. It's like a database bible. You have to work to get stuff out of it, and I'm only just realising that now, nearly halfway into the course.