This is a superb Curteich-Chicago C.T. Art-Colortone folio of 24 different linen cards, each with their own stock number, all captioned in Spanish.  Mailed with two Canal Zone stamps and full Balboa postmark, which did not include the year, but the folio copyright date is MCMXLIV (1944).  If you have any historical interest in Panama and/or the Canal Zone, this is definitely for your consideration.  Grade: 1