I have to wonder if people that buy the "for idiots" series of books expect that they were really written "for idiots"? Just because this book is called "pro", does not mean that it's some super high-level diatribe about active record. If you're such a pro, just read the source code for active record, all the docs you need are in there. If you want to actually see some examples and read a fair discussion, this book will suite you well. The worst thing about this volume, and most others from APRESS is that if you want an eBook version you have to pay additional fees and then get a "locked" pdf of the book. Wake up, APRESS - get with the Kindle program.