I agree with Jim. The BON has loads of great info but seeing cars up close and talking to long time owners and taking photos will get you enough knowledge to tell what you are looking at when you see cars for sale. If you are near South Carolina come join us this Friday and Saturday at our SOS/Invasion. Over 20 Sunbeams will be there!
After saying all of this, I have a nearly perfect BON signed by the author for sale. And like Jim said, it is pricey!