Blackstone, Harry (Sr. and Jr.). Two Window Cards. Including a Harry Blackstone Sr. three-color screen-printed window card (Chicago: Globe Poster Corp., ca. 1940s), a Blackstone Jr. “Instant Magic!” kit box (1981), and a signed Blackstone Jr. window card, vibrantly illustrated (some chipping on margins). Posters 22 x 14”, box 5 ¾ x 9 x 2 ½”.