Bill Weiss was concerned about passing on his knowledge and experience to others; he also wanted to attract younger hobbyists to philately. We often discussed on how to best pull the decades of experience out of his head and get it documented. Since he had seen so many US fakes and forgeries over years, he decided to try to capture this information in a document he named "FAKED AND ALTERED UNITED STATES STAMPS". In memory of Bill and as a contribution to the community, the document is now available on Stamp Smarter at link below. It is a good read for any hobbyist interested in US stamps.
Don
http://www.stampsmarter.com/fakes_landing.html