Lot of five 8.5x14" typed letters (one trimmed to 8.5x9.5") offered in a series by newspapers running the Buck Rogers daily strip and it's associated club, the Rocket Rangers. c. 1940s. First letter mentions enclosed "Official Membership Card" and mentions increased rank of Flight Lieutenant. Second letter is addressed to Veteran Solar Scout Rocket Rangers and mentions "Chief Explorer's Badge." Next letter was printed backwards w/directions "Hold This Secret Message Up To Mirror To Read It" at bottom. This letter promoted receiver to Veteran Rocket Ranger and came w/"Buck Rogers Rocket Ranger Insignia" badge. Next letter was issued to Veteran Buck Rogers Rocket Rangers and includes code. Last letter has been trimmed and was issued to Buck Rogers Rocket Rangers and includes "Special Orders No. 1" which were to observe the night sky. All letters have lightly aged and have been folded as mailed. Two letters have inking/penciling on indicated lines. Fine overall. Scarce.