All About Pocket Knives

I have a friend looking for a price guide book that includes Case XX knives, Boker knives, and other brands. Any help in finding one would be appreciated.

I don't collect Case knives, but I also don't know anyone who uses a printed pricing guide anymore. They're outdated before they are printed and distributed. Most people I know look at the sold price of the same knife on eBay to see what they're selling for. If it's a common knife you usually have a range of prices from which you can kind of figure from the condition of the knives listed and what price they are bringing.
I think that's far more accurate and gives you a better real time value than a printed list, because prices can fluctuate substantially in just a few weeks or months.