In Search of Threadless (A Source Guide for Threadless Diggers) by Mike Tucker
This book is still an excellent resource and is hard to find. Packed with information and maps. In great shape with just the tape missing from the binding edge. $25 plus actual postage (media rate is very reasonable)
NOTE: I'm selling these insulators on behalf of the Jim Fielding estate -- PayPal (no fee friends and family) or checks are both accepted - I'll provide instructions. I'll also be handling all the packing and mailing.