Your eight year old by Louise Bates Ames. I've read her other books in this series, starting with Your four year old, and found them to be right on target. They sort of pick up where the "What to expect" books leave off.
I like Ames's books better than the "What to expect" books because Ames isn't preachy and doesn't presume to tell you how to raise your child. She just writes about the behaviors that she and other researchers have observed over their years of research. It's very comforting to recognize the cycles of equilibrium and disequilibrium.
Though the cultural references to television shows and books are dated, the rest of the material is quite universal. The books were also written in the days before ADD so you won't find any mention of that.