Created in 1984 by Kevin Eastman and Peter Laird, Teenage Mutant Ninja Turtles #1 is the first appearance of Leonardo, Michaelangelo, Donatello and Raphael as well as their mentor, Splinter and their nemesis, The Shredder. It was meant to be a parody of Marvel's DAREDEVIL comics at the time, however the Turtles became insanely popular and are iconic characters in their own right to this day.
Only 3000 copies of the 1st printing were produced with many subsequent printings made after that. Because of the potential forgeries of this issue, it's important to denote certain indicators that can help determine if a copy is an original first printing.
First, this issue gives no indication what printing it is anywhere in the book (e.g. First Printing) as opposed to later printings which do. Additionally, the inside back cover will feature an ad for a fanzine called "GOBBLEDYGOOK." Finally, later printings will have nicer paper stock, as opposed to first printing copies which utilized more inexpensive newsprint-like paper.