Undoubtedly an illegal copy. Most unlikely to have been posted by the IMMM.
Scribd is IMO one of the major sites for ripped-off material - although to give them their due, they have taken down 3 illegal copies of my bibliography. I just wish they they would do some checking themselves, though.
Sorry if I sounded rather sharp in my response. No offence intended, but it is an issue that concerns me. If you see Adam's blog at http://www.alchemywebsite.com/weblog.html, he is continually being ripped off.
I am ambivalent. As an author, I oppose this type of behaviour.
As a bibliographer, I feel that I ought to include unauthorised Internet postings, in the same way that Gilbert does reprints in his Waite bibliography.
OTOH, because of the extensive nature of the Internet, I wonder if I should be giving these postings the 'oxygen of publicity' There does seem to be a bit of a difference between say a '60s paperback reprint and Internet material that is currently available.
I don't think that this little alchemy board is a primary source of information about illegal files. For me Google is the major culprit as they allow sites, that everyone knows are long term offenders distributing copyright material, to be indexed by their search engine. I am sure that people usually find things using the search engines.
Their own Google Books was obviously breaking copyright and they eventually settled the class action lawsuit by agreeing to pay the authors for use.