9.25x12" original, hand-addressed mailing envelope addressed to Lawrence Klein from Teenage Mutant Ninja Turtles co-creator Kevin Eastman, who sent Klein a handwritten letter on Eastman's personal letterhead (bearing a printed Eastman/Laird Turtles image) which is dated Dec. 10, 1984. In the letter, Eastman apologizes for the difficulty experienced by Klein in obtaining a copy of Teenage Mutant Ninja Turtles #1, while noting that issue #2 would release that very week and that Peter Laird would mail him a couple copies (see Laird signed letter, lot #8). The letter also mentions an enclosed "Original Pencil Sketch Of My Favorite Turtle, Raphael" (see following lot), a print of Raphael (which Eastman signed and dated "84", adding "My Favorite Turtle!" at bottom) and a few unpublished (at that time) photocopies of Leonardo sketches (one shows him in classic pose w/swords, the other showing him in classic Japanese armor) and "Sneak Peek Of A Book Coming In 1985." This "sneak peek" is a photocopy of the cover to Raphael #1, the Mirage Studios micro-series published in 1985. Letter is signed by Eastman at bottom and has been folded as mailed. All contents shows general lt. wear from mailing. Envelope has 2.5" tear to flap but all else is VF overall. Lawrence Klein Collection.