Sixth Column

No book-club issue is documented for the Gnome Press edition in the sources consulted. The standing trap is the retitling: the 1951 Signet mass-market paperback appeared as The Day After Tomorrow (original title given as Sixth Column on the cover/title page). That is a later reprint and a paperback "first thus" under the new title — it is not a first edition of the work, and copies are regularly mis-listed as such.