Jim, the reason why Ken's book is that price is that people are taking advantage of the fact that it is out of print, so they ask whatever price because they know what I know which is that Mr. Hamilton's book is THE BOOK on building automobile related dioramas. I am a happy and proud owner of a signed copy.
My advice is to keep looking for it in hobby shops, etc . . . and you might just run across it one day. The other option is to contact The Strand in New York and see if they can track you a copy for a more reasonable price.
Is it worth it, you bet!