[Thayer] Thayer ?Spirito? Great Radio Mystery Instructions and Form Letter. Los Angeles, 1924. Including a two-page prospectus form letter with stamped signature of Floyd Thayer introducing and advertising the piece, with two-page price list of parts and assembly; and 12-page stapled instructional packet. 4to. Mailing folds. Thayer?s outfit would allow an apparently ordinary radio to ?tune in on a ?mysterious unknown?? in which questions are answered by a ghostly voice from beyond. The expensive piece was advertised for only a brief period, and no complete original versions are known.