Ken,
This is a hard one to find. There are copies out there, but most folks want upwards of $75-$100 a copy. I have a seen a few sell on ebay and elsewhere for as little as $25 bucks in the past 12 months. My advice is to just keep hunting on the web. They do turn up.
If you can wait - there is a reprinting (revised to boot!) in the works. Not sure how far away it is though.
Josh