I just downloaded T.E.A.T.C.T. from the Harry Houdini collection, meaning, that this book belonged to HH himself.
In the first page of the book (the "frontispice"?) at the side of Erdnase's name, is written in pencil "Samuel Roberts". Also, the "S" and "W" are crossed in pencil, and under the two "E's" of Erdnase there is a mark in pencil.
Does this means that Houdini wrote the identity of Erdnase??