4x9.5" mailing envelope comes w/pair of 8.5x10.75" papers. Envelope features full figure Captain Marvel image at left. Some creases and folds from handling. Fine. Letter is on "Headquarters Captain Marvel Club" stationery and has full color image of Captain Marvel at left w/text "Capt. Marvel Appears In Whiz Comics - Captain Marvel Adventures - America's Greatest Comics On Sale At All News-Stands." Letter is dated Jul. 20, 1942 and is the follow-up letter to Jun., 1942 letter. Text starts "Boy, Oh Boy, I Guess All The Gang Liked The Idea Of Monthly Letters. Our Club Headquarters Are Just Full Of Your Swell Answers And A Lot Of You Ordered Those Snazzy Premiums." This letter notes membership was up to 90,000. Additional text refers to "Captain Marvel Adventures" #14 plus "Whiz Comics" #34 in which "We team up to help the United Nations in Another Smaxis at The Axis." This letter also mentions coded message sheet and this paper is included and is 2-sided in bw. Sheet has been clipped and has 3.5x5.5" square missing from center, bottom third of letter is loose but included. This was removed as "Special Captain Marvel Secret Code Message" was meant to be cut out and sent in for prize. Sheet just comes along. Letter is folded as issued, lightly aged and VF. Early and historic.