Information from the seller:
THEODORE COGSWELL Strange Holiday Greetings from the Edge
A three piece lot:
1) Postmarked 5 DEC 1983 SCRANTON, PA, a letter envelope addressed with typewriter to science fiction author Reginald Bretnor. Also typed on the envelope is "CONTENTS: ONE FREE HORSE." The return address sticker identifies the sender as Prof. Theodore R. Cogswell in the Dept. of Digital Enumeration at Miskatonic University in Chinchilla, which is probably a bunch of balderdash because this was from Theodore Cogswell, the golden-age science fiction short story virtuoso who rebounded in the silver-age with the best-selling "SPOCK, MESSIAH!" (Of course anything with "Spock" in the title was a best seller in the 70's...)
2) A "secrecy" envelope of sorts, inserted into the letter envelope with the bold declaration, "SEXUALLY EXPLICIT MATERIAL ENCLOSED."
and within the inner envelope
3) A tri-fold letter-size photocopy -- on the back of a Bureau of Land Management form for adopting wild horses and burros -- featuring Christmas greetings at top and bottom with some newspaper clippings in the middle that read: "Parents turn children into sex slaves," "Brother, Sister Plan Wedding," and "Miserable children can still be happy adults, shrink says." It is signed at the bottom in black ballpoint "Ted."